# *Official SLI / CF Thread*



## Kornowski

I thought it'd be a good idea for all the people that own an SLI or CF rig to share information and experiences. Also, I want to try and fill this thread with as much information as I can so that people thinking of going down the multiple card road can look here and find out what they need to know, or ask.

Feel free to post your pictures of your multiple card setups!



First off, a brief history of the two (Taken from Wikipedia);



*SLI's History*

Scalable Link Interface (SLI) is a brand name for a multi-GPU solution developed by Nvidia for linking two or more video cards together to produce a single output. SLI is an application of parallel processing for computer graphics, meant to increase the processing power available for graphics.

The name SLI was first used by 3dfx under the full name Scan-Line Interleave, which was introduced to the consumer market in 1998 and used in the Voodoo2 line of video cards. After buying out 3dfx, Nvidia acquired the technology but did not use it. Nvidia later reintroduced the SLI name in 2004 and intends for it to be used in modern computer systems based on the PCI Express (PCIe) bus. However, the technology behind the name SLI has changed dramatically.​


*CF's History*

CrossFire (also CrossFire X after release of the Spider desktop platform on November 19, 2007) is a brand name for ATI Technologies' multi-GPU solution, which competes with Scalable Link Interface (SLI) from NVIDIA. The technology allows up to four graphics cards to be used in a single computer to improve graphics performance. Although only recently announced for consumer level hardware, similar technology known as AMR has been used for some time in professional grade cards for flight simulators and similar applications available from Evans & Sutherland, ATI had also previously released a similar dual RAGE 128 consumer card called the Fury MAXX.​






A little information on each (Taken from Wikipedia, edited and information added by me);



*SLI Information* _< Click for more information_

The basic idea of SLI is to allow two or more graphics processing units (GPUs) to share the work load when rendering a 3D scene. Ideally, two identical graphics cards are installed in a motherboard that contains two PCI-Express x16 slots, set up in a master-slave configuration. Both cards are given the same part of the 3D scene to render, but effectively half of the work load is sent to the slave card through a connector called the SLI Bridge. As an example, the master card works on the top half of the scene while the slave card works on the bottom half. When the slave card is done, it sends its output to the master card, which combines the two images to form one and then outputs the final render to the monitor.

In its early implementations, motherboards capable of SLI required a special card which came with the motherboard. This card would fit into a socket usually located between both of the PCI-Express x16 slots. Depending on which way the card was inserted, the motherboard would either channel all 16 lanes into the primary PCI-Express x16 slot, or split lanes equally to both PCI-Express x16 slots. This was necessary as no motherboard at that time had enough PCI-Express lanes for both to have 16 lanes each. Thanks to the advancement in available PCI-Express lanes, most modern SLI-capable motherboards allow each video card to use all 16 lanes in both PCI-Express x16 slots.

The SLI bridge is used to reduce bandwidth constraints and send data between both graphics cards directly. It is possible to run SLI without using the bridge connector on a pair of low-end to mid-range graphics cards (e.g. 7100GS or 6600GT) with Nvidia's Forceware drivers 80.XX or later. Since these graphics cards do not use as much bandwidth, data can be relayed through just the chipsets on the motherboard. However, if no SLI bridge is used on two high-end graphics cards, the performance suffers severely as the chipset does not have enough bandwidth. nVidia have released a few cards along the time line that have been multiple card set-ups, in one card. Such examples include the 7950GX2 and the 9800GX2. These are two cards in SLI which on require one PCI-e bus.​






*CF Information* _< Click for more information_

With the release of the Radeon X1950 Pro (RV570 GPU), ATI has completely revised CrossFire's connection infrastructure to further eliminate the need for past Y-dongle/Master card and slave card configurations for CrossFire to operate. ATI's CrossFire connector is now a ribbon-like connector attached to the top of each graphics adapter, similar to nVidia's SLi bridges, but different in physical and logical natures.[5] As such, Master Cards no longer exist, and are not required for maximum performance. Two dongles can be used per card; these were put to full use with the release of CrossFire X. Radeon HD 2900 and HD 3000 series cards use the same ribbon connectors, but the HD 3800 series of cards only require one ribbon connector, to facilitate CrossFire X. Unlike older series of Radeon cards, different HD 3800 series cards can be combined in CrossFire, each with separate clock control.

Since the release of the codenamed Spider desktop platform from AMD on November 19, 2007, the CrossFire setup has been updated with support for a maximum of four video cards with the 790FX chipset; the CrossFire branding was then changed to "ATI CrossFire X". The setup, according to internal testing by AMD, will bring at least 3.2x performance increase in several games and applications which required massive graphics capabilities of the computer system, the setup is targeted to the enthusiast market. A later development include a dual GPU solution that was released in early 2008, the "ATI Radeon HD 3870 X2", featuring only one CrossFire connector for dual card, four GPU scalability.


​
*Drivers*

nVidia's Drivers can be found HERE.

ATI's Drivers can be found HERE.





*Multiple Monitors*

Multiple Monitors can be used with both SLI or CF, despite what people may say. It used to be the case that you'd have to either disable SLI / CF and have each card render it's own separate monitor or have an extra PCI card to render your second monitor, while you have the two other cards in SLI / CF render your main monitor. Now both companies have released drivers that allow more than one monitor to be used whilst still having SLI / CF enabled.

SLI - Any driver past 180.xx will allow the use of more than one monitor

CF - Any driver past ? Anybody fill me in here?





*FAQ's*



> Q: I have a question that has been niggiling me not that i can afford sli but what i dont get is how do you connect the screen to the card do you have 2 leads going into one or something? sorry if this sounds noobish
> 
> A: You see in the picture mac550 posted? All the cards (in that picture 3, normally only 2) are connected via something known as a bridge (the thing that has SLI written on it). This allows the cards to communicate with each other. Then, you plug your monitor into the top card and bam!




I will add questions and answers here once people ask some, or I find some. Or people suggest some, whatever. lol​


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## Bartmasta

I don't have it because I can't afford 2 cards.

I'd like to have it if I had the dough, though (lol rhyme).


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## mac550

*drools*


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## Calibretto

So like you can have two monitors, each using their own video card?


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## Kornowski

mac550 said:


> *drools*



Eeeww! Outdated technology! 



Calibretto said:


> So like you can have two monitors, each using their own video card?



Yeah, if you wanted. Or you can have two monitors, both using, both video cards.


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## mac550

Kornowski said:


> Eeeww! Outdated technology!



i no but i think they are the best looking GPU nVidia have ever done


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## Kornowski

mac550 said:


> i no but i think they are the best looking GPU nVidia have ever done



Agreed, they are pretty sick looking, but don't judge a book by it's cover!


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## andythelandy

i have a question that has been niggiling me not that i can afford sli but what i dont get is how do you connect the screen to the card do you have 2 leads going into one or something? sorry if this sounds noobish


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## Kornowski

You see in the picture mac550 posted? All the cards (in that picture 3, normally only 2) are connected via something known as a bridge (the thing that has SLI written on it). This allows the cards to communicate with each other. Then, you plug your monitor into the top card and bam!


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## andythelandy

Kornowski said:


> You see in the picture mac550 posted? All the cards (in that picture 3, normally only 2) are connected via something known as a bridge (the thing that has SLI written on it). This allows the cards to communicate with each other. Then, you plug your monitor into the top card and bam!



ah so you only need the lead from the main card i get you thanks.
o just thought of another q. lol will adding another gpu double the power or does it not work like that?


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## smoothjk

Adding another GPU does not double the power. Having 2 cards is more like 1.4x the power, but for some games at high resolutions, this extra boost can mean a big visible difference.

Is it just me, or does SLI seem to give much bigger gains than Crossfire? I was looking at tomshardware, FPS totals, and 2 Radeon 4850s in CF didn't even match up with one 4870. Meanwhile, 2 9600GTs in SLI scored very high.


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## andythelandy

smoothjk said:


> Adding another GPU does not double the power. Having 2 cards is more like 1.4x the power, but for some games at high resolutions, this extra boost can mean a big visible difference.
> 
> ok thanks


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## pies

I've heard a few bad things about toms hardware reviews.
Dual 4850's in crossfire has been amazing for me.
It plays crysis ultra high at 1440x900 resolution with 40-50 fps.


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## bullzi

Anybody have dual 4870's? I'm considering another soon..


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## g4m3rof1337

Awesome.












My laptop is also SLI.


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## scooter

bullzi said:


> Anybody have dual 4870's? I'm considering another soon..



Yes. they rock!


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## ThatGuy16

My 3870s






i plan on getting new heatsinks for the 4850s, maybe a couple VF1000s, or the new Duorb X thats suppose to be coming out.


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## scooter

I hate you^^^


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## bullzi

scooter said:


> I hate you^^^



^^^ So do I.. 

I do have the same case though,  he pretty much has the exact setup I'm shootin' for minus the 4850's.


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## Kornowski

*Anybody got any questions they need answering, or any questions they know the answer to that I can throw into the FAQ area?*

Here's my SLI rig;


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## Mez

You should add hybrid sli/cf since many people don't know what it is.


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## Mez

Kornowski said:


> *Anybody got any questions they need answering, or any questions they know the answer to that I can throw into the FAQ area?*
> 
> Here's my SLI rig;



God if the lights in the picture hurts my eyes, I don't want to know what its like irl O_O


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## mep916

fitseries3 at techpowerup successfully quad Crossfired 4870x2s and used a GTX 260 for Physx. 






This post describes how to do it.


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## Respital

Wow, looks like a beast!

Any benchmarks for that rig mep?


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## mep916

Respital said:


> Any benchmarks for that rig mep?



Yeah, that's all he does is bench.


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## Respital

That's a good bench. Although i have no idea what's good on the new vantage.


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## mep916

Respital said:


> That's a good bench. Although i have no idea what's good on the new vantage.



That's pretty high for the performance setting.


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## bullzi

That's insane, I can't even imagine the gameplay on that. I can totally max out FC2 and I get extremely playable framerates on a single 4870, can't wait until I have two


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## Scubie67

I guess its an all right benchmark. I figure he is doing the best he can.Bless his Heart


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## Kornowski

Thought I'd bump this, in case anybody had any good FAQ's I could put in there... Also, maybe sticky it? I see a lot of people making threads asking about SLI and CF...


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## awildgoose

Kornowski said:


> Eeeww! Outdated technology!
> 
> 
> 
> Yeah, if you wanted. Or you can have two monitors, both using, both video cards.



What do you mean old technology? what card is that?


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## oregon

8800 Ultra I think


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## Computer_Freak

mep916 said:


> fitseries3 at techpowerup successfully quad Crossfired 4870x2s and used a GTX 260 for Physx.
> 
> 
> 
> 
> 
> 
> This post describes how to do it.



how do the 4870X2 breathe?


Also, what works better, GTX 260 SLI or 4870 CF


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## mep916

Computer_Freak said:


> Also, what works better, GTX 260 SLI or 4870 CF



http://www.hardocp.com/article.html?art=MTU1OCwxLCxoZW50aHVzaWFzdA==


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## CdnAudiophile

mep916 said:


> Yeah, that's all he does is bench.



Thats not much of a gain. I score 24xxx at 3.8 with only my 2 cards, no physx card.


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## mep916

THERMAL-REACTOR said:


> Thats not much of a gain. I score 24xxx at 3.8 with only my 2 cards, no physx card.



From what I've seen, Physx can give you a 2 to 3K increase in your score. I posted it mostly cuz I though it was cool that he successfully enabled 5 GPUs...it took some work but he got it running.


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## Droogie

Pretty informative thread, sticky worthy I'd say.


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## Kornowski

tknick90 said:


> Pretty informative thread, sticky worthy I'd say.



Thanks, man.


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## mac550

Kornowski said:


> Eeeww! Outdated technology!



maybe but i would still swap my 8800 GT's for a couple 



awildgoose said:


> What do you mean old technology? what card is that?
> 
> 
> 
> oregon said:
> 
> 
> 
> 8800 Ultra I think
Click to expand...


yup, they are the 8800 Ultra's


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## Kornowski

mac550 said:


> maybe but i would still swap my 8800 GT's for a couple



Yeah... true! lol e-penis!


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## funkysnair

my new crossfire setup 

2x4850's.... loving it












sorry for poor pics, used mobile phone


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## CdnAudiophile

funkysnair said:


> my new crossfire setup
> 
> 2x4850's.... loving it
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> sorry for poor pics, used mobile phone


 Looks awesome man, great job! I like the way those water loops flow in the case. Do you have any pictures of it in the dark?


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## funkysnair

THERMAL-REACTOR said:


> Looks awesome man, great job! I like the way those water loops flow in the case. Do you have any pictures of it in the dark?



thanx!!

no ill get some good photos with a decent cammera soon..

one of my uv cathodes has just deceased so its not as good in the dark now, looks nice all glowing blue


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## pdc76

i added a second 8800gtx to my rig not too long ago and i saw a nice increase in performance. more recently i added a third 8800gtx for 3-way sli, and i saw only a small increase.

i'm using 3dmark06 as a gauge. single card i was getting 12000's, 2 cards shot me up to 18000's, but with 3 i'm barely breaking 20000's (and that's only after overclocking as much as i can, otherwise i'm in the 19000's). am i doing something wrong?

i tried enabling physics, disabling it, and changing other performance settings, but that only seems to give me a lower score. is 3dmark06 not setup for more than 2 cards or something?


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## Kornowski

Nah, you've not done anything wrong. Two cards will see a fair bit of a difference, but three will hardly see any. It's a little overkill, a nice set up non the less though!


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## Okedokey

Kornowski said:


> *Anybody got any questions they need answering, or any questions they know the answer to that I can throw into the FAQ area?*
> 
> Here's my SLI rig;



underpowered man.

plus where do you little ****s get the money>  you must live at home!!


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## Kornowski

bigfellla said:


> underpowered man.



How so?



bigfellla said:


> plus where do you little ****s get the money>  you must live at home!!



The same way everybody else does, I have a job.


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## Russian777

Not Bad Set-Up For 6gb GDDR5.


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## Bodaggit23

Russian777 said:


> Not Bad Set-Up For 6gb GDDR5.


Who's pc is that?


Russian777 said:


> hey, get one gtx 280 evga, and you will be good for a long time to come.
> 
> Thats What I got now. Sli Is Garbage.


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## Russian777

Bodaggit23 said:


> Who's pc is that?




Hey its a custom one that i built for my friend.


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## Bodaggit23

Russian777 said:


> Hey its a custom one that i built for my friend.


lol 
But SLI is garbage right? Only good enough for your buddy. rofl


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## Russian777

you wont feel a big diff in sli, only if you want to fly with it!!!


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## bullzi

Well he's running crossfire. ATI's crossfire scales MUCH better than Nvidia's SLI with multiple card configs.


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## neversay5

mac550 said:


> *drools*



I like this one


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## shelby_vn

Thought I'd bump this, in case anybody had any good FAQ's I could put in there... Also, maybe sticky it? I see a lot of people making threads asking about SLI and CF...


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## Mr Marshmallow

Sorry if this is threadmancy, but it is stickied, sooo...

In your guys' experience, which is better, crossfire or SLI? I know what Russian777 thinks, but how about the rest of you?


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## ScottALot

Oh god. Can I get an extra BFG Tech 9800GT to run either SLI or Crossfire on my Gigabyte GA790X UD4P Mobo?


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## JEEPjeep

im looking to hook up a three monitor setup with two videocards in sli. am i right for thinking that i just hook up the three monitors to the two video cards?

playing FPS games and MMORPG


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## zeroo

Hi, can any one help/advise me. I am building a gaming pc, not sure what to go with.
I have a ASUS M3N-HT Deluxe/HDMI and droping in a Phenom II X4 940 Black Edition Quad-core Processor - 3.00 GHz, 4 x 2 gigDDR2
Just not sure weather to go with 2 ATI 4870/4890 radeons or 3 nvid 8800 GT/Ultra or any other nvid that can be used in a 3 way sli config.
Thanks for looking


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## just a noob

zeroo said:


> Hi, can any one help/advise me. I am building a gaming pc, not sure what to go with.
> I have a ASUS M3N-HT Deluxe/HDMI and droping in a Phenom II X4 940 Black Edition Quad-core Processor - 3.00 GHz, 4 x 2 gigDDR2
> Just not sure weather to go with 2 ATI 4870/4890 radeons or 3 nvid 8800 GT/Ultra or any other nvid that can be used in a 3 way sli config.
> Thanks for looking



either 3 4890's(if you can find a board that's decent that is), or 3 gtx 280's(you can pick up refurbs on the evga website for $250 each)


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## G25r8cer

JEEPjeep said:


> im looking to hook up a three monitor setup with two videocards in sli. am i right for thinking that i just hook up the three monitors to the two video cards?
> 
> playing FPS games and MMORPG



No I believe you cannot run 3 monitors with sli. Without sli then, yes. Or you could just get a 5870 which supports 3monitors via 2 dvi and 1 displayport.


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## just a noob

sli seems to be working for me  i don't know if you can use 3 moniters with sli or not, but i do know you can use 2(ask kornowaski about it, because i know he uses 2 monitors)


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## awildgoose

Well I got another 9600GT for free so I decided to put it in my new system (i5-750, GA-P55M-UD4 only 2G of ram though  ).
Don't have any pictures but I took a screenie to prove it.


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## Ryeong

bullzi said:


> Well he's running crossfire. ATI's crossfire scales MUCH better than Nvidia's SLI with multiple card configs.



I can't say that i agree. I went from 32 fps on very high, 1080p in crysis with one gtx 275 to over 60 with two in sli.. I have a mininum of 90% fps increase in my games, depending on patch/drivers.


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## just a noob

Ryeong said:


> I can't say that i agree. I went from 32 fps on very high, 1080p in crysis with one gtx 275 to over 60 with two in sli.. I have a mininum of 90% fps increase in my games, depending on patch/drivers.



proof?


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## Ryeong

just a noob said:


> proof?



*Here, this is a benchmark i did myself.

This is how i did it:

I Returned to stock settings. From what you can see in my sign to stock for gtx 275..*
*
Both benchmarks: 1920x1080, 4xAA, 16xAF, High settings (max), DX 10..*

[The benches i uploaded got deleted?


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## just a noob

That's nice(i never really benchmarked my 285's so i have no idea how they performed), next time would you mind resizing the pictures please?


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## CamCracker

mac550 said:


> *drools*



That looks amazing!  You build it?


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## Ryeong

just a noob said:


> That's nice(i never really benchmarked my 285's so i have no idea how they performed), next time would you mind resizing the pictures please?



Hehe, i forgot to resize 

I get more fps overclocked, but i think the stock settings is a good way to compare.. Two 285's in sli should get much better results. Also, 480 is said to scale better.

I think the coding in heaven is really good. This is only version 1.0. Whats better in version 2.0?


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## Triiton

Looking into SLI...Currently use BFG GeForce 9800GT 1GB and I am wondering whether it is worth doubling up on my current config?


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## Shane

Yeah i think itd be worth it if you can get a second 8800/9800GT cheap.


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## Triiton

aight...have a 500w PSU. Guess moving up to a 700-750w PSU would be also in the making....My index scores on my comp are currently 7+ but graphics is at 6.9....by Windows 7 levels though. 

So from all I have heard and looked into a second VC couldn't hurt.


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## bluecity

*Im really wanting to get into Crossfire, to be doing it for the first time I want to match the card I got with the exact same, which so far has been a dead end (its unavalible ever place I look) my luck if I change brand names I will have issues. Anybody got a http://www.newegg.com/Product/Produ...56&cm_re=GV-R487D5-1GD-_-14-125-256-_-Product  or have any ideas were I can get one?*


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## joh06937

bluecity said:


> *Im really wanting to get into Crossfire, to be doing it for the first time I want to match the card I got with the exact same, which so far has been a dead end (its unavalible ever place I look) my luck if I change brand names I will have issues. Anybody got a http://www.newegg.com/Product/Produ...56&cm_re=GV-R487D5-1GD-_-14-125-256-_-Product  or have any ideas were I can get one?*



you don't need to get the EXACT same one (brand), just an hd 4870 (or possibly an hd 4850 or hd 4890).


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## Shane

joh06937 said:


> you don't need to get the EXACT same one (brand), just an hd 4870 (or possibly an hd 4850 or hd 4890).



Yeah as far as im aware it can be any brand/make...not sure if memory size on the cards matter? eg...512mb and say a 1gb together.

I would try and stick with the same card/brand though just to prevent any problems.


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## bluecity

Nevakonaza said:


> Yeah as far as im aware it can be any brand/make...not sure if memory size on the cards matter? eg...512mb and say a 1gb together.
> 
> I would try and stick with the same card/brand though just to prevent any problems.



Im looking now at cards from Gigabyte that match Effective Memory Clock 	900MHz (3.6Gbps)
Memory Size 	1GB
Memory Interface 	256-bit
Memory Type 	GDDR5
There expensive


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## joh06937

don't worry about the clocks, you can always oc them. also, if you want more help, i suggest starting a thread in video cards and monitors before people get mad...


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## beizhou

:good:


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