Hello all THG forum users , i have seen many of my friends in this forum making mistakes about SLI/CrossFire technology and also there are many questions about it in here , so i have decided to write a guide that helps you undertand these technologies better , so lets start :
What is SLI ?
NVIDIA SLI is a platform that allows you to scale graphics performance by combining multiple NVIDIA® graphics solutions in a single system.
What is CrossFire ?
CrossFire is a high-performance PC Gaming Platform technology that enables multiple ATI Radeon graphics cards and a CrossFire-ready motherboard in a single computer to increase graphics quality and performance.
What is CrossFireX(Quad CrossFire)?
I found a very good definition for it in techreport.com:
CrossFireX is, quite simply, an extension of the CrossFire dual-GPU feature to three and four GPUs.
Here is a good chart about the cards and motherboards which support CrossFire,CrossFireX and the compatibility list:
From Anandtech.com :Aside from potential performance scalability, there is also the capability to support up to 8 monitors from one system with 4 graphics cards installed.
What is AMD Hybrid CrossFire?
Its a technology from AMD which allows an integrated graphics and low-end discrete graphics in CrossFire mode.
You are basically taking two very slow GPUs and making one not-so-slow GPU.
This can only be done with AMD chipsets and AMD/ATI Graphics.
What is Nvidia Hybrid SLI?
I found a very good information in Hothardware.com and here is it:
NVIDIA's Hybrid SLI technology gives users the abilty to pair an IGP, or mGPU (motherboard GPU), with a discreet graphics card, or cards, for two new mdoes of operation. NVIDIA calls these new modes Hybrid Power and GeForce Boost.
GeForce Boost does what its name suggests. By coupling the motherboard's integrated GPU with a discreet graphics card, the 3D rendering workload is shared between the two GPUs for a boost in performance. Currently, GeForce Boost is only supported by GeForce 8400 GS and 8500 GT discreet cards, as for the IGP, only the next-gen nForce 700a series of chipsets due to arrive this quarter will be supported initially.
What is Nvidia 3-Way SLI Technology?
Its a technology from Nvidia which allows 3 Nvidia Graphic cards to work with each other.
System Requirements and Specifications:
Three GeForce 8800 Ultra or GeForce 8800 GTX or 9800GTX Graphics Cards
NVIDIA nForce 680i SLI,780i SLI,790i SLI,790iULTRA SLI Motherboard
Intel dual or quad-core Core 2 processor (AMD platform to be announced)
Power Supply With Minimum Peak Power of 1100 Watts
Four 6-pin and two 8-pin PCI-E Power Connectors or
Six 6-pin PCI-E Power Connectors
3-Way SLI Connector
Proper and Robust Case Airflow
New Windows Vista Hotfix For 3-Way SLI (KB945149)
A very very important note: You can only use Nvidia Geforce GTX 280,GTX 260,9800GTX, 8800GTX and 8800 ULTRA in 3-Way SLI Technology, because these cards have dual SLI connections,but other cards like 8800GT,8800GTS or other 88xx series don't have dual SLI connections, So you can't use them in 3-Way SLI Technology.
Can you use SLI on a CrossFire board or can you use CrossFire on a SLI board ?
Well , in general , the answer is NO. But it's said that if you hack the drivers , you can use SLI on a CrossFire board or CrossFire on a SLI board.
Caution:There is no guarantee that if you hack the drivers then you use SLI on a CrossFire Motherboard or CrossFire on a SLI board, so do it at your own risk!
Do the cards have to be same model?
I answer it with an example:
You have a NVIDIA Geforce 7800GTX 256, and you want to add another card , the second card has to be 7800GTX exactly.
But what about the memory? Can you add a 7800GTX 512 and use that with 7800GTX 256?
It's recommended to use a 7800GTX 256 with a 7800GTX 256 and 7800GTX 512 with 7800GTX 512.
However you can use a 7800GTX 256 with 7800GTX 512 , BUT the 7800GTX 512 will lower its clock to operate with the 256 one, so it wont have its true power. (This option isn't recommended )
What about brands ?
Well the brand doesnt matter , again for example , you can use a XFX card with a EVGA card , or a SAPPHIRE card with a DIAMOND card , just make sure they have the same memory and same clocks.
What will happend if 2 cards have the same amount of memory but one has higher clocks than the other?
One of the best ways to learn is to make examples.
You have a 8800GT(Normal edition,no OverClocks) and you want to add another 8800GT(Which is OverClocked),then:
1_The OverClocked one will lower its clocks to reach the Non-OverClocked card.
2_You can OverClock your card(The one that has Stock frequencies) and reach the OverClocked card.
Remember, you cant ALWAYS OverClock the normal card to reach the other card,because it may not OverClock that much and may become unstable.
WARNING:There are many exceptions in Computer Hardware, for example "Mousemonkey" a member of this forum has told me that when he puts his ASUS 7900GT card (Which is at stock speeds) with a XFX 7900GT(A OverClocked card) the ASUS one raise its clock to reach the XFX one which is an exception and as i said exceptions are alot in Computer Hardware.
Do SLI or CrossFire always improve performance ?
Not Always , there are some games that dont take advantage of SLI or CrossFire , so you wont see a difference between 2 cards and 1 card in those games , but in games that take advantage of SLI or CrossFire , 2 cards will perform better than one.
WARNING: Some RAMs have SLI or CrossFire logo on them. Many people ask if they are the only RAMs which support SLI or Crossfire.
Well thats wrong,there are many RAMs which dont have SLI or CrossFire logo but you can use SLI or CrossFire with them without any problem.
What are the power requirements for SLI or CrossFire ?
For each card , the Power requirement is different , if you want to know if your Power Supply can handle SLI or CrossFire , check here
For NVIDIA cards, go here:
http://www.slizone.com/object/slizone_build_psu.html WARNING: There are some Power Supplies which aren't in the List , but they are compatible , you have to check the manufactures sites too.
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.)
This(MultiGPU at lower resolutions) has changed now, i mean in the first years of MiltiGPU technology the drivers werent as good as they are now and also not all games took advantage from MultiGPU, but things have gotten better(but not the best, because there are still games that dont take advantage MultiGPU like Flight Simluator X and there are still lots of driver problems too.)So in some of today games that really drain a lot of power from GPU, MultiGPU performs good at low resolutions (again in some games).
Also as i said , it depends on what games (with what settings) you play , for example if you just want to play games at good settings (with not everything at maximum settings) then MultiGPU technology isn't needed , but if you want to play with every option at maximum settings, then SLI would help alot.
Caution: Due to some problems (like Drivers and etc) in some games, a single card (like X1900XT) may beat 2 1900XT in CrossFire mode! so dont always think that 2 cards will beat one card.
Should i get 2 midrange cards instead of one high-end card ?
No, again i will answer this with example. 2 8600GT or single 8800gts ? this is one of the most common questions in forums. single 8800GTS (320 or 640) will beat 2 8600GT in games , because a single 8800GTS has more stream processors , more memory clock , more bandwidth. so again 1 single high-end card will beat 2 midrange cards.
Should i get 2 High-End cards or one Ultra-High-end ?
This is again one of the most asked questions. Many ask that 2 9600GT 512 will cost like a single 8800GTX(or even cheaper). Which is a better buy?
Well, in most cases , 2 9600GT 512 cards will beat a 8800GTX card(In games that benefit MultiGPU technlogy). But in some other games a 8800GTX beats 2 9600 GT in SLI mode.(This happens when you mostly play at very high resolutions and you enable AA and AF).
Also remember that 2 9600GT 512 cards will be more noisier and also they will produce more heat than one single 8800GTX.
Do SLI or CrossFire double the memory ?
This is one the questions that many people make mistake understanding it .
The answer is NO , SLI or CrossFire doesnt double the memory , You have a 512MB card , adding another card wont make your memory 1GB, it still will be 512MB
Another example :
A game needs 512MB card to run at maximum settings , and you have a 256MB card , and you think if you add another 256MB card , your memory will be 512MB and thats not true.
You may see this mistake in many sites.
Which is better , SLI or CrossFire ?
Well , you cant say exactly which is better , in some games SLI does better than CrossFire and in some games CorssFire does better than SLI, for benchmarks and tests , go to Tomshardware charts:
http://www23.tomshardware.com/graphics_sli2007.html
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 getting the best performance out of Multi-GPU cards,you need a Motherboard that supports Multi-GPU at dual(Or more) 16x mode like Nvidia 790i ULTRA SLI, Nvidia790i SLI, Nvidia 780i SLI, Nvidia 680i( As i said, NVIDIA 790i ULTRA SLI ,790i SLI ,780i SLI and 680i SLI 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.
However,there are some expections too,for example EVGA has a 750i Motherboard(The model of it is
EVGA 750i SLI FTW)Which supports SLI at dual 16x mode unlike many 750i Motherboards which support SLI 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.
Here are some benchmarks that help you understand it better:
Dual 16x vs Dual 8x (ASUS A8N32-SLI DELUXE vs ASUS A8N-SLI PREMIUM) Its an old but good article:
http://www.xbitlabs.com/articles/m [...] eluxe.html
Geforce 7 Family:
NVIDIA GEFORCE 7950GX2(Remember, you may think that because 7950GX2 is actually "2 cards attached to one" then you need a SLI motherboard to use it, but you dont, for single 7950GX2, u will need just one PCI-E 16x slot.
NVIDIA GEFORCE 7900GTX
NVIDIA GEFORCE 7950GT
NVIDIA GEFORCE 7900GT
NVIDIA GEFORCE 7900GS
NVIDIA GEFORCE 7800GTX 512
NVIDIA GEFORCE 7800GTX 256
NVIDIA GEFORCE 7800GT
NVIDIA GEFORCE 7600GT
NVIDIA GEFORCE 7600GS
NVIDIA GEFORCE 7300GT
NVIDIA GEFORCE 7300GS
NVIDIA GEFORCE 7300LE
AMD/ATI HD 4870X2(Read the note about HD 3870X2,its the same for HD 4870X2)
AMD/ATI HD 4870
AMD/ATI HD 4850
AMD/ATI HD 3870X2(Warning:The HD 3870X2 is NOT 2 cards (like Nvidia 9800GX2).Its actually 2 GPUs on one card and it has 1 PCB* compared to 2 PCBs of 9800GX2,so you "Don't" need a CrossFire board to use this card,it requires only one slot.)
AMD/ATI HD3870
AMD/ATI HD 3850
AMD/ATI HD 3830
AMD/ATI HD 3650
AMD/ATI HD 3470
AMD/AT HD 3450
AMD/ATI HD 2900XT
AMD/ATI HD 2900PRO
AMD/ATI HD 2900GT
AMD/ATI HD 2600XT
AMD/ATI HD 2600 PRO
AMD/ATI HD 2400XT
AMD/ATI HD 2400 PRO
AMD/ATI X850 Family:
AMD/ATI X850XT-PE
AMD/ATI X850XT
AMD/ATI X850 PRO
*: emp and 4745454b (They are good friends of mine in this forum who help me very much and i thank them for their help)gave me a good definiton and explanation of PCB to me: PCB stands for Printed Circuit Board, its the hard "plastic-like" colored part in a graphics card/motherboard.
9800GX2 has 2 PCBs so its actually 2 cards attached to one.But HD 3870X2 has 1 PCB and its actually 2 GPUs on card which has the power of 2 HD 3870s.
Warning: AMD/ATI X1800/X1900/X1950 cards need a CrossFire-Edition of them to run in CrossFire mode.But for HD Family its different, they don't need CrossFire-Edition, they just cant work with each other for example a
HD 2600 works with another HD 2600 just fine.
Also please read the note about CrossFireX at the first parts of this guide.
If you found something wrong in this guide please tell me to fix it,also i thank all who helped me in this topic.
Also if you have seen that i have put a link from other site,its because that it had a very good information about MULTI-GPU technology.
So i hope reading this guide will help you understanding MultiGPU technology better , if you have any question, simply ask and i am glad to answer
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XPS M1730,IntelCore2Duo T9300@2.5GHZ,2x8800MGTX in SLI,4GB DDR2 667 RAM,DUAL 250GB 7200 RPM,VISTA HP with SP1,17" with 1920x1200 resolution
^ glad u liked it
dare i say : "plz make it sticky ?"
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XPS M1730,IntelCore2Duo T9300@2.5GHZ,2x8800MGTX in SLI,4GB DDR2 667 RAM,DUAL 250GB 7200 RPM,VISTA HP with SP1,17" with 1920x1200 resolution
Nothing I didn't already know, but regardless of that it is indeed VERY helpful for people who are confused on the subject. I suggest it get stickied but with a title change... like "READ THIS before asking any questions about MultiGPU technology" or similar.
Also you should add that it is usually not worth it getting dual cards over a single higher end one and the reasons behind it, but still very good job.
thanx EMP ,well unfortunately i can only Do QUICK EDIT , when i go to EDIT THIS MESSAGE , it says u are not allowed to edit this message, so i cant change the TOPIC name , but i edited the message , thanx to u
P.S , i know many know about SLI or CrossFire , but because i have seen people making mistake or they have some questions , i decided to make this
thx again
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XPS M1730,IntelCore2Duo T9300@2.5GHZ,2x8800MGTX in SLI,4GB DDR2 667 RAM,DUAL 250GB 7200 RPM,VISTA HP with SP1,17" with 1920x1200 resolution
Thanks Maizar, I've seen countless posts about SLI and CF where the posters clearly didn't know the basics, hopefully this will cut down on a lot of misinformed posting.
Then again ignorance is caused by a lack of reading useful information, so lets hope this gets sticky status so that people will read it.
hmmm, another thought, put "teen porn" as the subject and i guarantee the number of hits for this guide will increase dramatically.
well, you have two choices, keep bumping it or get it made a sticky as otherwise it is of no use. If people were prepared to search the forums before posting then they would all that you posted already.
still it is good of you to take the time to do that sort of thing, i long ago gave up and hope that this sort of post would affect the majority of newbies who come here for advice.
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XPS M1730,IntelCore2Duo T9300@2.5GHZ,2x8800MGTX in SLI,4GB DDR2 667 RAM,DUAL 250GB 7200 RPM,VISTA HP with SP1,17" with 1920x1200 resolution
To stranger stranger,While i agree with you in princaple.
Main problem with that is although it is a good idea in theory its mainly new people to the forum who ask these questions/so dont know about stickys.Also it would help if the search feature actually worked instead of saying every topic searched(even ones i posted as a test) were no longer found.
To Go Oman
Being Ignorant of the facts and being Ignorant are two differant things and alot of the time being misinformed is confused as being the same thing i have seen people argue untill they were blue in the face (hard to gague on a forum i know but get the point i think).But totally beleive that what they thought they knew was true.
The internet is a gold mine of info but it takes a while for the cream to rise to the top.
I have done it myself and will probably do it again,when a source proves time and time to be reliable then we will defend it up to a point,its just some people cant see that point.
Mactronix
Also, you should add in that while it can increase the maximum FPS, it will bring up your minimum FPS, as well, which results in MUCH better gameplay than ANY increase in max. frames (unless the max is under 30 or so.)
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The ability to speak does not make you intelligent.
e6320 @ 3.15GHz (450x7, 1.400v) ** GA-965P-DS3 1.3 (F11 BIOS)
2x1GB G.Skill 900MHz 4-4-3-5-2T 2.2v ** XFX 8800GTS 632Mhz/962MHz(1924MHz DDR)
320GB WD3200AAKS ** Lite-On
i have talked about pairing NVIDIA cards , for CorssFire its the same
to flip_x, its said if u update the graphic card driver, it will be done
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XPS M1730,IntelCore2Duo T9300@2.5GHZ,2x8800MGTX in SLI,4GB DDR2 667 RAM,DUAL 250GB 7200 RPM,VISTA HP with SP1,17" with 1920x1200 resolution
How did they get the BlackBird from HP to run xfire on a striker extreme board??
Having been on an Air Force base that had SR-71 Blackbirds, if I tried to tell you, I'd get arrested and you might end up in the next cell.
As far as running Crossfire on a Striker mobo, that involves installing hacks that may or may not work on a given combination of parts, and waiting for drivers that neither Nvidia nor ATI will ever provide.
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Evil lurks in the databanks as it lurked in the streets of yesteryear. But it was never the streets that were evil.
how can i tell a moderator to make this stickie ? PM him ?
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XPS M1730,IntelCore2Duo T9300@2.5GHZ,2x8800MGTX in SLI,4GB DDR2 667 RAM,DUAL 250GB 7200 RPM,VISTA HP with SP1,17" with 1920x1200 resolution
ldlnic001@mail.uct.ac.za