SLI / CrossFire FAQs - page 3

1270 answers Last reply
  1. Edited again, (Nvidi 3-way SLI, Hybrid CrossFire and some other things)
    Reply to Maziar
  2. Nice FAQ, very through.
    Reply to TheForumMember
  3. This thread needs to be on every forum out there. I have so many people asking me why they can't "SLI" two 3870's with a Besides the fact that people are needing to use their own brains, more posts like this really help.

    Reply to T8RR8R
  4. thakn you very much TheForumMember and T8RR8R :)
    Reply to Maziar
  5. i bought 2 cards ati 3850 saphire and they are configured in crossfire.
    i got a couple of problems which i would appreaciate if someone has the same problem and provides with any info :
    1. after a couple of second in game call of duty 4 it crashes and when i try to open it agan it says DIRECTX ERROR ps. i am playing with ati 7.11 drivers.
    My question is there any other configuration in CATALYST?
    Reply to wolfheart1979
  6. mate you asked me with a PM and i will answer you there, so please don't post your question here too.
    Reply to Maziar
  7. Sooooo, I take it I can't use the old 7600GT my brother gave me (free :D) with my 7800GT in SLI? Seeing as they are different models...
    Reply to ishbog
  8. yeah, 7800 + 7600 = No SLI
    Reply to nukemaster
  9. exact answer ^^
    thanks nukemaster :)
    Reply to Maziar
  10. I am glad I read this forum. What would you guys recomend for watching blue ray and playing games on a 50 inch plasma - two 3870 cards or an upcoming 9800 card?
    Reply to chron1
  11. If the rumors are true and a 9800 is %30 faster than a 8800 ULTRA, then i would recommend 1 9800. but you have to wait and see what the exact specifications are.
    Reply to Maziar
  12. Edited
    Reply to Maziar
  13. Thanks for the quick reply. I do not mind waiting. All I really want is to have the best possible picture quality for movies and occasional gaming.
    Reply to chron1
  14. Edited (Added Nvidia Hybrid SLI )
    Reply to Maziar
  15. im looking for a setup for 1280x1024 and was wondering about crossfire I have a ASUS P5K mobo
    Reply to random1283
  16. Is it really necessary to use SLI or CrossFire ?
    Well , it really depends mostly on the resolutions and games you play , resolutions like 1920x1200 and higher benefit more from SLI or CrossFire than resolutions like 1600x1200 or lower (I dont mean SLI or CrossFire wont be good for resolutions like 1600x1200 or lower , i am just saying that SLI or CrossFire shines in higher resolutions.)

    So i dont recommend CrossFire for your resolution, also :

    A note about Motherboards:
    Some Motherboards support Multi-GPU Technology at Dual 16x mode, some support it at Dual 8x mode and some support it at 16x 4x mode, what are the differences?

    Well for gettig the best performance out of Multi-GPU,you need a Motherboard that supports Multi-GPU at
    dual 16x mode like Nvidia 780i SLI, NVIDIA 680i( As i said, NVIDIA 780I and 680i support 3-Way SLI too),Nvidia 590i SLI, Nvidia nForce4 SLI 16x, ATI CrossFire Xpress 3200 or Intel X38 chipsets.

    Dual 8x is a very good configuration too,it doesnt have alot of difference with Dual 16x and its cheaper too.
    Chipests like Nvidia 750i SLI, Nvidia 650i SLI,NVIDIA 570i SLI, NVIDIA nForce4 SLI, ATI Radeon Xpress 200, Intel 975x and ONLY 2 Intel P35 boards(ASUS BLITZ FORMULA and ASUS BLITZ EXTREME) support Multi-GPU at dual 8x mode.

    The last one is 16x 4x, this one is the weakest and doesn't perform very good compared to dual 8x or dual 16x,so i won't recommend it for Multi-GPU configuration. Intel P35 and P965 chipsets support Multi-GPU at
    16x 4x mode.

    Dual 8x vs 16x 4x (ASUS P5B DELUXE vs P5W-DH DELUXE)
    Reply to Maziar
  17. Does anyone out there know if the spider platform can accomodate three cards? or are the options limited to 1,2 and 4.
    Reply to Farmer Brown

    Scalable graphics you crave on your budget—up to four cards all running in
    ATI CrossFireX™ mode, with support for up to eight monitors

    Well i think when it says up to 4,then it can support 3 cards too.
    Reply to Maziar
  19. Would using 2 cards that have more Stream Processors get more benefit from SLi and CrossFire than cards with lower Strream Processors? For instance say :

    EVGA GeForce 8800 GT Video Card - 512MB DDR3, PCI Express 2.0, SLI Ready, (Dual Link) Dual DVI, HDTV, Video Card with 112 stream processors for 259.99
    Visiontek Radeon HD 3870 Video Card - 512MB GDDR4, PCI Express 2.0, CrossFireX Ready, Dual DVI, HDTV, HDMI Support, Video Card with 320 stream processors for 249.99

    I know it 2 different tech but its the only 2 cards i found in the same price range with a large difference in stream processors.
    Reply to valorean
  20. "Warning: AMD/ATI cards need a CrossFire edition of its model to run at CrossFire mode (With the exception od AMD/ATI HD series)"

    I believe "od" is suposed to be "of"
    Reply to yay
  21. to valorean:
    the stream processors in 88xx series are different with the stream processors in HD 38xx or HD 29xx series.
    As you see in the benchmarks,HD 3850/HD 3870/ 2900XT have
    320 stream processors, and for example 8800GTX has 112 stream processors, and a 8800TGX (which has 112 stream processors) beats 2900XT (which has 320 stream processors)

    Here is a useful link :

    The 320 individual stream processing units in R600 are arranged in 4 groups of 80 SIMD arrays and each functional unit is arranged as a 5-way superscalar shader processor. In contrast, NVIDIA's G80 has up to 8 groups of 16 (128 total) fully generalized, fully decoupled, scalar, stream processors, but keep in mind the SPs in G80 run in a separate domain and can be clocked as high as 1.5GHz. In ATI's R600, each functional SP unit can handle 5 scalar floating point MAD instructions per clock. And one of the five shader processors (the fatter one in the image above) can also handle transcendentals as well. In each shader processor, there is also a branch execution unit that handles flow control and conditional operations and a number of general purpose registers to store input data, temporary values, and output data.

    to yay:
    yes,thanks i will edit it :)
    Reply to Maziar
  22. Thanks for the info posted on here, Emp has also gave me advice on my 8600GT that I thought about putting in SLI but I have decided to RMA it to newegg yesterday and will be getting new card or cards.

    I am debating either a MSI 8600GTS Dimiond series in SLI, new egg has them for $138 dollars right now with a $20 dollar rebate, and one of the main reason's I am really considering these cards is that it has a HDMI output on it. With my $100.00 credit from my 8600GT that put the cost of the two at $280.00 - $40 on the rebate -$100 = $140.00 for the sli setup. Stream processors are only 32 on a single card and not sure how good this is. Ram is only 256 DDR3 clock is 700 i believe.

    I am sure that emp if he responds will tell me to get the 8800GTX or ultra, but I am not wanting to spend over $300 at this time. If I can find a good 8800 series that can beat the MSI sli setup that is around $300 with out my $100 credit I think I can swing an extra $200.

    Sorry for all the info but any advice would be helpful, cuz I am sending my card back today and will need to make a choice very soon, because my new custom build will be a paper wieght until I get the new card here.
    Reply to medjohnson77
  23. Your math is a bit off. Its $138 * 2 - $20 + shipping. Check the rebate info, only one per household/person. (Unless you are shipping one somewhere else, you'll only get one.) Not a big problem, but I thought I'd point that out.

    8600GTS in SLI isn't enough to handle a 3850 AFAIK. The 3850 is pretty much the best sub $200 card out there right now. The 256MB 8800GT isn't a bad idea either. If I remember correctly, the 3850 and the 256MB 8800GT are pretty close, so I'd try to get either of these.

    Last, not meaning to be rude, but I'm not sure the SLI sticky is the correct place to post this. Posting back to your old thread, or PMing someone would probably have been a better idea.
    Reply to 4745454b
  24. Agreed, thank you 4745454b(i am glad to know your name, since typing your username takes a lot of time :d ) for your help,i appreciate it. :)

    Also if you PM somebody,then talk about it in that PM,dont post it in this topic :)
    Reply to Maziar
  25. Edited
    Reply to Maziar
  26. Great post. I wonder when will be the HD3870x2 be included.
    Reply to goonting
  27. Its included :)
    Reply to Maziar
  28. So Sorry guys,

    I went a BFG 8800GTS 512Mb card, couldn't be happier!
    Reply to medjohnson77
  29. Glad to hear it mate :)
    Reply to Maziar
  30. Another thing to add:

    Neither SLI or CrossFire will support the use of multiple monitors when enabled!

    This means you will have to disable the feature in order to get multiple monitor display (and enabling or disabling the feature typically requires a reboot).
    Reply to Oh SoS
  31. You don't need to reboot to turn a second monitor on or off. From what a coworker says, you don't need to reboot to turn SLI on or off either. I don't know about the status of CF though.
    Reply to 4745454b
  32. 4745454b said:
    You don't need to reboot to turn a second monitor on or off. From what a coworker says, you don't need to reboot to turn SLI on or off either. I don't know about the status of CF though.

    nope, you do not need a restart with CF, even my ancient setup does not need that, all you need to do is disable it through the CCC, i have to do it with certain games, well CoH and dawn of war only(damn relic) and also if i want to rotate my display to portrait mode as forums like toms display better especially when they get changed and don't expand to fill the damn screen.(hint, hint Toms.)

    I said "typically"...heh.

    I haven't owned an ATI card in over a decade, but I know from personal experience that disabling/enable SLI often requires a seems to be dependent on the amount of virtual memory & ram in use.
    And for someone who tends to leave the computer running w/ anti-virus running 24/7, rebooting (and clearing the virtual memory & ram) is not necessarily a bad thing...just kind of annoying when I want to go from playing a game to watching a movie on my big screen.
    Reply to Oh SoS
  33. Oh SoS said:
    Another thing to add:

    Neither SLI or CrossFire will support the use of multiple monitors when enabled!

    This means you will have to disable the feature in order to get multiple monitor display (and enabling or disabling the feature typically requires a reboot).

    Crossfirex will support more then one monitor in CrossFire mode (sweeeeeeeeeeeeeet)
    Reply to hassa
  34. First of all again thank you 4745454b and also strangestr anger for helping me in this thread.

    Aside from potential performance scalability, there is also the capability to support up to 8 monitors from one system with 4 graphics cards installed. While this isn't as universally desired, it could be something fun to play with. We don't currently have a platform solution that we can use to test this yet, but we will certainly test this when we are able.
    Reply to Maziar
  35. Can you have 4 or 2 HD3870's on a 790FX
    Reply to klobnitrones
  36. correction HD3870x2's
    Reply to klobnitrones

    Also note that the 3870 X2 has only a single CrossFire edge connector along the top of its PCB. It has only one because the other connection is already utilized on the PCB. Although the Radeon HD 3870 X2 is equipped with a CrossFire connector, at this time drivers are not available that will allow end users to link two of these cards together for quad-GPU CrossFireX. Those drivers are coming though.
    Reply to Maziar
  38. So you'd have to get an AMD mobo and 4 cards to get mutli-monitor support out of CrossFire X?

    I'll pass.
    but at least I can get 2 cards and not have to deal w/ the stupid dongle anymore, yeah?
    Reply to Oh SoS
  39. Edited
    Reply to Maziar
  40. Edited again thanx to my good friend 4745454b :)
    Reply to Maziar
  41. Edited
    Reply to Maziar
  42. Well I found an error right off the bat. You say that CrossfireX requires a motherboard with four PCIe slots. This is not true, My Gigabyte GA-MA790FX-DS5 supports CrossfireX with only two slots. How? Well you can use two 3870X2 cards on this board and then you have CrossfireX.

    There is also a DFI board with the 790FX chipset that supports CrossfireX and it only has three PCIe slots.
    Reply to stoner133
  43. a couple things to fix on your post. where you discribed all the cards in each series
    1. the 3870gx2 is NOT 2 cards (like nvidea) . its 2 gpus on one card
    2. you do not need a crossfire edition card with the 2xxx and 3xxx series cards all cards in the series can crossfire. if memory serves the 1950 i believe didnt need it eather but the 1900 and down does

    other then the little fixes good post. :D
    Reply to circeseye
  44. circesey is correct, 1800 and 1900 series cards needed a Crossfire Master card and it connected to the second card with a Dongle cable between the two cards on the outside of the case. The did away with that with the 1950 cards.

    The 3870X2 sort of works like two 1900's but instead it has the Crossfire chip between the two GPU's on the one card and this chip is identical to the chip used on the 1900 Crossfire Master card.
    Reply to stoner133
  45. 1_3870X2 is like 2 cards attached to one so i am not wrong about that

    2_Thanks for that i will fix it
    Reply to Maziar
  46. Edited
    Reply to Maziar
  47. I have to agree with Maziar on this IS 2 cards since if it was just 2 gpus on one card they would not need video ram for each gpu...just one set of ram for both.....they are just crossfire on a stick. so its JUST like nvidia.
    Reply to nukemaster
  48. nukemaster said:
    I have to agree with Maziar on this IS 2 cards since if it was just 2 gpus on one card they would not need video ram for each gpu...just one set of ram for both.....they are just crossfire on a stick. so its JUST like nvidia.

    1 card
    Reply to kpo6969
  49. I think u misunderstood it
    I meant HD 3870X2 itself is a single card but its actually 2 card attached to each other just like 7950GX2 which needs only one single PCI-E 16x to run
    Reply to Maziar
  50. I disagree with Maz and nuke. The 3870x2 has only one PCB, hence it is one card. The 9800GX2 has two PCBs, so it is two cards. You can argue against this all you want, but there is only one PCB.

    In the grand scheme of things, who cares. Be aware that each uses SLI/CF, and each card has its own benefits/draw backs. Whether it is one card or two doesn't really matter that much.
    Reply to 4745454b
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