AMD>INTEL
04-09-2006, 02:25 AM
Supported Hardware
Basically, the only motherboards that support SLI at the moment are Nforce 4 based boards. I believe that VIA are working on an alternative as are ULi but these are not yet available. All the major motherboard manufacturers now have SLI boards available. You can find some reviews here for Gigabyte, and here for Asus. And here is a general look at Nforce4. DFI have now released their rather tastey looking SLI board, and MSI have one on the market aswell. Here is a great test of all four boards from anandtech. And for further comparason, you can find another group test HERE.
As of the 6th April 2005, Nvidia have launched their Nforce 4 Platform for Intel CPU's. Therefore you are now no longer limited to choosing an AMD system if you want an SLI rig. The Nforce 4 Intel edition seems to be holding out well compared to other intel based chipsets. One thing to bear in mind though is that for some reason they dont support the Pentium D 820 CPU's, although they do support all other Pentium D chips. HERE you can find a review of MSI's P4N Diamond, and Gigabytes GA-8N SLI Royal, and a general overview of Intel Edition SLI can be found HERE
In terms of graphics cards, Nvidia initially anounced that only the 6600GT , 6800GT and 6800ultra would support SLI. This has now changed, and with the recent driver releases (77.72's onwards) all cards right down to 6600's from the 7800GTX support SLI. One exception to this though is that 6800GTO's (cut down 12 pipe version of the GT) DO NOT Support SLI, and while it will recognise them as SLI capable, linking two together results in massive Graphical corruption, as one Guru3d member unfortunately found out!
One other thing to bear in mind, is that at the moment, SLI has NO dual monitor support, therefore you can only use one monitor in SLI mode.
The most important thing to bear in mind is that any hardware you buy has this:
stamped somwhere on the box.
If you are concerned about compatability of your Graphics cards, have a look at nvidias brand new SLI site HERE
And for your reference, here are Guru3d's very own SLI findings. Firstly, 6600GT SLI, secondly, a review of Gigabytes interesting dual GPU card, the 3D1 and finally, by far the most impressive setups you could own, dual 7800GTX and 7800GT's
There has also been a few misconceptions as to compatibility, and which cards can be used together. It used to be the case that you had to have 2 identical cards with same bios and from the same manufacturer. This is now no longer the case. Nvidia has updated their drivers so cards will work with different bios's, although they still have to be from the same manufacturer. However, HardOCP have reported that from driver release 80 this will change, and u will be able to use cards from different manufacturers in SLI configuration.
Application compatability
Much has been made of the fact that SLI will only work if there are 'profiles' for a game present in the drivers. You can find the list of officially supported apps here There are now around 100 or more applications that support SLI including benchmarks. However, it is no longer the case that you are stuck with single card support if there isnt an 'official' profile, as Nvidia provides you with the tools you need to create your own SLI profiles, including the ability to choose SLI rendering modes, for all your games within their drivers. You can find instructions on that here. Performance will vary from game to game, and depending on which rendering mode you use. Bear in mind that older games may not benifit from SLI due to CPU limitation.
It is directly because of this that nvidia have added additional AA support as an SLI rendering mode to take advantage of games CPU limited in SLI mode. This gives you the option of utilising that graphics horse power for better IQ where higher FPS may not be necessary. There are currently two AA modes. SLI 8x and SLI 16x. These should work on ALL games and are available in drivers from 77.76 onwards. You can find details on how this works here
Note - There is a bug in some games 'in-game' screenshot function, and with apps like FRAPS that take screenshots, as they take the shot before the final image has been composited and output to your monitor. Therefore screenshots will not necassarily show SLI AA as being applied. The only way currently to ensure you get a screen shot with SLI AA applied is by using PRINT SCREEN key on your keyboard. So dont panic if you screenshots dont look as good as you expect!
There are also third party applications now becoming available for people to set SLI profiles for themselves. One such app is nhancer developed by Guru3d member Grestorn and looks like a very promising little app. I have been using it and it works very well, enabling SLI in all games I tried it on, although I must say that performance increase varied greatly from game to game as with using profiles in the drivers. Also note that some games prefer one rendering mode (i.e. SFR or AFR) over another. For example KOTOR II would crash with AA and AF enabled on SFR, but runs fine with AFR. I recommend you give it a try and see what works! As well as SLI profiles, it also lets you edit all your game profiles in a much more user friendly way than the nvidia CP.
If you want to see what effect SLI is having on your games and how its distributing load between the cards, you can enable 'load balancing' under the multi GPU tab in the drivers. This will display green lines that divide the screen into two areas, one for each GPU. Please note, that some people have been confused by this as it occasionally set to 'on' as defualt, so if u see green lines over your games, dont panic... just disable load balancing!
Is SLI for you?
As with all new technology, it is best to go into it expecting to fiddle, tweak and hone to get it all set up and working as you like. Things obviously improve as they gain more support. Having said that, i was impressed at how easy my system was to get going.
There are two real reasons for investing in SLI.
1) to get next gen performance NOW. This is the expensive option, and one only for die hard enthusiasts with the money to spend (like me! ) The biggest thing to remember if you are investing in 2x7800GT/GTX's right away is that you will need a CPU to match. Even a top of the line FX57 will bottleneck these cards, so bare this in mind. The main advantage to this is that you will not need to upgrade for a VERY long time. The CPU issue has become a little more complex with the addition of dual core CPU's to the market. Please bear in mind that if you are building a gaming SLI rig, then you will see no benifit from dual core CPU's in games. Infact, a top of the line X2 4800 will only perform similar to a single core 4000 , and costs around the same as an FX-57. Depending on what your building your rig for, the FX-57 may be the better bet if gaming is your primary concern, or you could save some pennies and get a 4000 as you would experience the same in game performance as the X2 4800 .
2) As a basis for an upgrade platform. With PCI-E, socket 939, and all the other features of Nforce 4, it makes a very good basis for a system that can be added to in the long run. For example, you could buy one card now, and then double your performance on the cheap at a later date. This works particularly well for the more affordable 6600GT, although bare in mind if you intend to get two of these it might be better to invest in a single 6800GT as it leaves you with more options in the future, although this depends on cost. If you intend to go down this route, make sure both cards are compatible.
Power
While an SLI rig may provide you with the ultimate in gaming power, bear in mind it is also going to require the ultimate in electrical power. One of the most important things to think about when upgrading to SLI is a decent powersupply. This is particularly important when 2 6800GT's/Ultras are thrown into the equasion and even 7800GT's/GTX's even though they have slightly lower power consumption.
Make sure its from a decent manufacturer, like Antec, Enermax or OCZ, and that the Amps on each rail are extrememly good. An ATX 2 compliant PSU is also a definate plus if you can get one For reference, I am running on an Enermax 600Watt Noisetaker, with 2x12v lines at 18amps each. It is totally stable so far, but then you would expect it from that level of PSU. I recommend a minimum of a 500watt PSU with at least 30amps on the 12v rail for those using high end cards (i.e. 6800GT or higher) in SLI configuration.
Monitors & Screen Resolution
If you are considering a 6800Ultra or especially 7800GT/GTX based system, it is essential that you consider your monitor. Particlularly in the case of TFT's. Bare in mind that you really will not see the benifit of a SLI rig at this level running at anything less than 1600x1200, due to CPU limitation, and really the only advantage would be higher benchmark scores. All that power will just not be used on a 17" TFT with 1280x1024 native res, and i would consider a resolution of 1024x768 a complete waste!!!
Basically, if you arent bothered about benchmarks, and can only run at a resolution no higher than 1280x1024, dont expect to be 'blown away'. Maybe consider a monitor upgrade and a single card in the short term, you can always add a second card down the line.
Drivers
I have tested various drivers, and have finally settled on the 77.77's as the current best as these support all games on nvidias application list as well as adding SLI AA modes, and including support for use of different bios's as mentioned above. Any previous drivers to this will not. I have also found these to be the most stable for SLI. I have tried the earlier BETA 71.xx series, although I had issues such as an annoying screen twitch on desktop, only half the screen displaying when watching a movie and some timing issues. The 67.02's were ok, but desktop IQ seems improved on the 03's. Nividas 66.93's from their site are perfectly stable, but the 67.03's seem to offer better performance. I have been running on the 66.77's for a few weeks now aswell, and have experienced no game bugs or SLI issues and perform similar to the 67.03's. I have heard good reports about the 76.41's however, and I shall be trying these shortly. Drivers can be found in the Guru 3d downloads section
note - There is a bug on the 71.84 drivers that will not allow you to overclock in SLI mode. Apparantly the 76.41's overcome this issue although this is not confirmed.
SLI Rendering Modes
When setting your own profiles in the drivers (or 3rd party app if you choose) there are various different rendering modes available. Some will work better than others depending on the game. Here is a quick rundown on the modes available. See the link above (under application compatibility) for details on how to setup your own profiles.
SFR (Split Frame Rendering) - basically, the the top portion of the frame is rendered by one card, and the bottom by the other. This isnt a 50 50 split, but is measured 'on the fly' so, say sky doesnt need as much power to render, so the card doing this may do 60 or 65% of the frame, and the card rendering the bottom half, (the more detailed floor) would do 35%
AFR (and AFR2) - Alternate Frame Rendering - basically all odd frames are rendered by one GPU and all even frames rendered by the other GPU. I havnt been able to find out exactly what the difference is between AFR and AFR two - I think its just a compatilbilty adjustment.
SLI 8x & SLI 16x Modes - Applies 8x/16x AA. In 16x AA mode both GPU's render the SAME frame, and apply 8x AA to each, but off set (i.e. applied at different points) the image is then composited creating 16xAA on the viewed frame.
Auto-Select - Does exactly what it says, auto selects the rendering mode. For all games with official SLI profiles, it will default to the rendering mode defined in the profile. Other games will run in single card mode unless u have created a user profile stating otherwise
Multi-GPU - All games are rendered in SLI, in SFR mode. Official Profiles over-ride this where necessary, as do User defined profiles.
Single Card - Well... a bit self explanitory really!
Overclocking in SLI mode
Overclocking in SLI mode is just the same as with a single card. Whether using Coolbits or Rivatuner, only ONE set of Core and memory speeds will be displayed. Dont worry, this is totally normal. When you overclock either the memory or core clock slider it is overclocking BOTH cards. The reason you cant see two sets of controls (one for each card) is because clock speeds have to be sync'ed for SLI to work properly. If there were a set for each card, you could run one card at a different speed to the other, leading to possible stability issues.
One final note. Riva Tuner will only display clock frequencies and temp values for the primary card, and not the secondary one. Again, this is normal. When you overclock using Riva Tuner you are automatically overclocking both cards.
Monitoring Dual GPU temps for LCD displays/Rivatuner/MBM5
As you may be aware, Riva tuner doesnt support temp monitoring for both GPU's, so the only way you can monitor this, is through the Nvidia CP. However, there is a work around using Motherboard Monitor 5 instead of Rivatuner.You can monitor both ambient and core temps like this, and even send the data to an LCD screen like the Matrix Orbital for BOTH cards seperately. You need to grab a copy of Motherboard Monitor 5, and mod it to recognise nforce 4 motherboards. Its quite simple really... see HERE.
And see here to see how to get MBM5 to recognise SLI temps on the 2nd GPU see HERE.
You dont even need to run Riva Tuner at all now, just MBM5 instead. Once you have set all that up, and if you are lucky enough to own one (like me ) you can use a plug in to your LCD software (im using LCDC with the MBM5 plugin and it works great) to program screens and display the temps on your front panel LCD screen. It works great and allows you to monitor your GPU temps for both graphics cards while gaming.
Hope that helps.
Over to you guyz
Thats enough of me banging on, so its over to you to provide your experiences, or feel free to ask questions. I am particularly interested for input from those of you with 6600GT's/vanilla 6800's as most of the issues I have seen with SLI have been to do with these cards. These are also the level of system that I think will become most popular as they are more affordable. Feel free to post benchmarks, driver and hardware recommendations, overclocking results and any tips that you have regarding SLI
Basically, the only motherboards that support SLI at the moment are Nforce 4 based boards. I believe that VIA are working on an alternative as are ULi but these are not yet available. All the major motherboard manufacturers now have SLI boards available. You can find some reviews here for Gigabyte, and here for Asus. And here is a general look at Nforce4. DFI have now released their rather tastey looking SLI board, and MSI have one on the market aswell. Here is a great test of all four boards from anandtech. And for further comparason, you can find another group test HERE.
As of the 6th April 2005, Nvidia have launched their Nforce 4 Platform for Intel CPU's. Therefore you are now no longer limited to choosing an AMD system if you want an SLI rig. The Nforce 4 Intel edition seems to be holding out well compared to other intel based chipsets. One thing to bear in mind though is that for some reason they dont support the Pentium D 820 CPU's, although they do support all other Pentium D chips. HERE you can find a review of MSI's P4N Diamond, and Gigabytes GA-8N SLI Royal, and a general overview of Intel Edition SLI can be found HERE
In terms of graphics cards, Nvidia initially anounced that only the 6600GT , 6800GT and 6800ultra would support SLI. This has now changed, and with the recent driver releases (77.72's onwards) all cards right down to 6600's from the 7800GTX support SLI. One exception to this though is that 6800GTO's (cut down 12 pipe version of the GT) DO NOT Support SLI, and while it will recognise them as SLI capable, linking two together results in massive Graphical corruption, as one Guru3d member unfortunately found out!
One other thing to bear in mind, is that at the moment, SLI has NO dual monitor support, therefore you can only use one monitor in SLI mode.
The most important thing to bear in mind is that any hardware you buy has this:
stamped somwhere on the box.
If you are concerned about compatability of your Graphics cards, have a look at nvidias brand new SLI site HERE
And for your reference, here are Guru3d's very own SLI findings. Firstly, 6600GT SLI, secondly, a review of Gigabytes interesting dual GPU card, the 3D1 and finally, by far the most impressive setups you could own, dual 7800GTX and 7800GT's
There has also been a few misconceptions as to compatibility, and which cards can be used together. It used to be the case that you had to have 2 identical cards with same bios and from the same manufacturer. This is now no longer the case. Nvidia has updated their drivers so cards will work with different bios's, although they still have to be from the same manufacturer. However, HardOCP have reported that from driver release 80 this will change, and u will be able to use cards from different manufacturers in SLI configuration.
Application compatability
Much has been made of the fact that SLI will only work if there are 'profiles' for a game present in the drivers. You can find the list of officially supported apps here There are now around 100 or more applications that support SLI including benchmarks. However, it is no longer the case that you are stuck with single card support if there isnt an 'official' profile, as Nvidia provides you with the tools you need to create your own SLI profiles, including the ability to choose SLI rendering modes, for all your games within their drivers. You can find instructions on that here. Performance will vary from game to game, and depending on which rendering mode you use. Bear in mind that older games may not benifit from SLI due to CPU limitation.
It is directly because of this that nvidia have added additional AA support as an SLI rendering mode to take advantage of games CPU limited in SLI mode. This gives you the option of utilising that graphics horse power for better IQ where higher FPS may not be necessary. There are currently two AA modes. SLI 8x and SLI 16x. These should work on ALL games and are available in drivers from 77.76 onwards. You can find details on how this works here
Note - There is a bug in some games 'in-game' screenshot function, and with apps like FRAPS that take screenshots, as they take the shot before the final image has been composited and output to your monitor. Therefore screenshots will not necassarily show SLI AA as being applied. The only way currently to ensure you get a screen shot with SLI AA applied is by using PRINT SCREEN key on your keyboard. So dont panic if you screenshots dont look as good as you expect!
There are also third party applications now becoming available for people to set SLI profiles for themselves. One such app is nhancer developed by Guru3d member Grestorn and looks like a very promising little app. I have been using it and it works very well, enabling SLI in all games I tried it on, although I must say that performance increase varied greatly from game to game as with using profiles in the drivers. Also note that some games prefer one rendering mode (i.e. SFR or AFR) over another. For example KOTOR II would crash with AA and AF enabled on SFR, but runs fine with AFR. I recommend you give it a try and see what works! As well as SLI profiles, it also lets you edit all your game profiles in a much more user friendly way than the nvidia CP.
If you want to see what effect SLI is having on your games and how its distributing load between the cards, you can enable 'load balancing' under the multi GPU tab in the drivers. This will display green lines that divide the screen into two areas, one for each GPU. Please note, that some people have been confused by this as it occasionally set to 'on' as defualt, so if u see green lines over your games, dont panic... just disable load balancing!
Is SLI for you?
As with all new technology, it is best to go into it expecting to fiddle, tweak and hone to get it all set up and working as you like. Things obviously improve as they gain more support. Having said that, i was impressed at how easy my system was to get going.
There are two real reasons for investing in SLI.
1) to get next gen performance NOW. This is the expensive option, and one only for die hard enthusiasts with the money to spend (like me! ) The biggest thing to remember if you are investing in 2x7800GT/GTX's right away is that you will need a CPU to match. Even a top of the line FX57 will bottleneck these cards, so bare this in mind. The main advantage to this is that you will not need to upgrade for a VERY long time. The CPU issue has become a little more complex with the addition of dual core CPU's to the market. Please bear in mind that if you are building a gaming SLI rig, then you will see no benifit from dual core CPU's in games. Infact, a top of the line X2 4800 will only perform similar to a single core 4000 , and costs around the same as an FX-57. Depending on what your building your rig for, the FX-57 may be the better bet if gaming is your primary concern, or you could save some pennies and get a 4000 as you would experience the same in game performance as the X2 4800 .
2) As a basis for an upgrade platform. With PCI-E, socket 939, and all the other features of Nforce 4, it makes a very good basis for a system that can be added to in the long run. For example, you could buy one card now, and then double your performance on the cheap at a later date. This works particularly well for the more affordable 6600GT, although bare in mind if you intend to get two of these it might be better to invest in a single 6800GT as it leaves you with more options in the future, although this depends on cost. If you intend to go down this route, make sure both cards are compatible.
Power
While an SLI rig may provide you with the ultimate in gaming power, bear in mind it is also going to require the ultimate in electrical power. One of the most important things to think about when upgrading to SLI is a decent powersupply. This is particularly important when 2 6800GT's/Ultras are thrown into the equasion and even 7800GT's/GTX's even though they have slightly lower power consumption.
Make sure its from a decent manufacturer, like Antec, Enermax or OCZ, and that the Amps on each rail are extrememly good. An ATX 2 compliant PSU is also a definate plus if you can get one For reference, I am running on an Enermax 600Watt Noisetaker, with 2x12v lines at 18amps each. It is totally stable so far, but then you would expect it from that level of PSU. I recommend a minimum of a 500watt PSU with at least 30amps on the 12v rail for those using high end cards (i.e. 6800GT or higher) in SLI configuration.
Monitors & Screen Resolution
If you are considering a 6800Ultra or especially 7800GT/GTX based system, it is essential that you consider your monitor. Particlularly in the case of TFT's. Bare in mind that you really will not see the benifit of a SLI rig at this level running at anything less than 1600x1200, due to CPU limitation, and really the only advantage would be higher benchmark scores. All that power will just not be used on a 17" TFT with 1280x1024 native res, and i would consider a resolution of 1024x768 a complete waste!!!
Basically, if you arent bothered about benchmarks, and can only run at a resolution no higher than 1280x1024, dont expect to be 'blown away'. Maybe consider a monitor upgrade and a single card in the short term, you can always add a second card down the line.
Drivers
I have tested various drivers, and have finally settled on the 77.77's as the current best as these support all games on nvidias application list as well as adding SLI AA modes, and including support for use of different bios's as mentioned above. Any previous drivers to this will not. I have also found these to be the most stable for SLI. I have tried the earlier BETA 71.xx series, although I had issues such as an annoying screen twitch on desktop, only half the screen displaying when watching a movie and some timing issues. The 67.02's were ok, but desktop IQ seems improved on the 03's. Nividas 66.93's from their site are perfectly stable, but the 67.03's seem to offer better performance. I have been running on the 66.77's for a few weeks now aswell, and have experienced no game bugs or SLI issues and perform similar to the 67.03's. I have heard good reports about the 76.41's however, and I shall be trying these shortly. Drivers can be found in the Guru 3d downloads section
note - There is a bug on the 71.84 drivers that will not allow you to overclock in SLI mode. Apparantly the 76.41's overcome this issue although this is not confirmed.
SLI Rendering Modes
When setting your own profiles in the drivers (or 3rd party app if you choose) there are various different rendering modes available. Some will work better than others depending on the game. Here is a quick rundown on the modes available. See the link above (under application compatibility) for details on how to setup your own profiles.
SFR (Split Frame Rendering) - basically, the the top portion of the frame is rendered by one card, and the bottom by the other. This isnt a 50 50 split, but is measured 'on the fly' so, say sky doesnt need as much power to render, so the card doing this may do 60 or 65% of the frame, and the card rendering the bottom half, (the more detailed floor) would do 35%
AFR (and AFR2) - Alternate Frame Rendering - basically all odd frames are rendered by one GPU and all even frames rendered by the other GPU. I havnt been able to find out exactly what the difference is between AFR and AFR two - I think its just a compatilbilty adjustment.
SLI 8x & SLI 16x Modes - Applies 8x/16x AA. In 16x AA mode both GPU's render the SAME frame, and apply 8x AA to each, but off set (i.e. applied at different points) the image is then composited creating 16xAA on the viewed frame.
Auto-Select - Does exactly what it says, auto selects the rendering mode. For all games with official SLI profiles, it will default to the rendering mode defined in the profile. Other games will run in single card mode unless u have created a user profile stating otherwise
Multi-GPU - All games are rendered in SLI, in SFR mode. Official Profiles over-ride this where necessary, as do User defined profiles.
Single Card - Well... a bit self explanitory really!
Overclocking in SLI mode
Overclocking in SLI mode is just the same as with a single card. Whether using Coolbits or Rivatuner, only ONE set of Core and memory speeds will be displayed. Dont worry, this is totally normal. When you overclock either the memory or core clock slider it is overclocking BOTH cards. The reason you cant see two sets of controls (one for each card) is because clock speeds have to be sync'ed for SLI to work properly. If there were a set for each card, you could run one card at a different speed to the other, leading to possible stability issues.
One final note. Riva Tuner will only display clock frequencies and temp values for the primary card, and not the secondary one. Again, this is normal. When you overclock using Riva Tuner you are automatically overclocking both cards.
Monitoring Dual GPU temps for LCD displays/Rivatuner/MBM5
As you may be aware, Riva tuner doesnt support temp monitoring for both GPU's, so the only way you can monitor this, is through the Nvidia CP. However, there is a work around using Motherboard Monitor 5 instead of Rivatuner.You can monitor both ambient and core temps like this, and even send the data to an LCD screen like the Matrix Orbital for BOTH cards seperately. You need to grab a copy of Motherboard Monitor 5, and mod it to recognise nforce 4 motherboards. Its quite simple really... see HERE.
And see here to see how to get MBM5 to recognise SLI temps on the 2nd GPU see HERE.
You dont even need to run Riva Tuner at all now, just MBM5 instead. Once you have set all that up, and if you are lucky enough to own one (like me ) you can use a plug in to your LCD software (im using LCDC with the MBM5 plugin and it works great) to program screens and display the temps on your front panel LCD screen. It works great and allows you to monitor your GPU temps for both graphics cards while gaming.
Hope that helps.
Over to you guyz
Thats enough of me banging on, so its over to you to provide your experiences, or feel free to ask questions. I am particularly interested for input from those of you with 6600GT's/vanilla 6800's as most of the issues I have seen with SLI have been to do with these cards. These are also the level of system that I think will become most popular as they are more affordable. Feel free to post benchmarks, driver and hardware recommendations, overclocking results and any tips that you have regarding SLI