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Can you explain what you need to do for crossfire or SLI

SkScotchegg

SkScotchegg

SkScotchegg

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Hey there, Please can you explain to me, I understand you need to find a motherboard that says crossfire supported, or SLI supported. But when you buy two graphics card how do you know which two to buy?

Can I buy any 2 nvidia cards and any two ATI cards and aslong as they're PCI express they will work as crossfire or SLI?

Thanks allot,


SkScotchegg:D
 
SkScotchegg said:
Hey there, Please can you explain to me, I understand you need to find a motherboard that says crossfire supported, or SLI supported. But when you buy two graphics card how do you know which two to buy?

Can I buy any 2 nvidia cards and any two ATI cards and aslong as they're PCI express they will work as crossfire or SLI?

Thanks allot,


SkScotchegg:D
Click to expand...

2 Nvidia cards + SLI mainboard for SLI

2 ATI cards + Crossfire mainboard for Cross fire

You can't use SLI in an Crossfire board or Crossfire in a SLI board though a single Nvidia card is fine is a Crossfire board and a single ATI card is fine in an SLI board.

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As long as you have an SLi capable board, yes they would.

However you'd be far better going with a single GTX.

SLi is a good idea but two cards run hot, drain a lot of power, and in the majority of cases are poor value for money. You're also relying on SLi profiles to give good performance.

There are instances where SLi/Crossfire gives very good value for money though, for example a pair of 7900GTX cards would probably set you back around £150 for both, but would give 8800GTX performance in certain games.
 
Oh right I see, I just thought from what I heard that these days you should buy two graphics cards for twice the speed, but is that not always the case? I dont want to buy two cards if it's not going to work out that way, soppose I might aswell buy one?

Cheers in advance,


SkScotchegg:D
 
I've just helped my friend in the same situation, made him get an 8800GTX, then you'll be absolutely sure that you'll get great performance.
 
Tute said:
As long as you have an SLi capable board, yes they would.

However you'd be far better going with a single GTX.

SLi is a good idea but two cards run hot, drain a lot of power, and in the majority of cases are poor value for money. You're also relying on SLi profiles to give good performance.

There are instances where SLi/Crossfire gives very good value for money though, for example a pair of 7900GTX cards would probably set you back around £150 for both, but would give 8800GTX performance in certain games.
Click to expand...

I had a pair of overclocked 7900GT's in SLI, I got the second one cheap second hand and it gave me a real performance just from a single card. Even though My 3dmark score hasn't gon up all that much with a 2900Pro @ XT speed, games eg. BIOshock are a lot faster.

SLI is good in some situations eg. a boost to an older system, or if you have a ample budget and want to get the absolute best system. Otherwise a single more powerful card is the prefered option.

Final though...

Many SLI board are split so with a single card gets 16 PCI-E lanes and a pair of cards get 8 PCI-E lanes each. Some cards, eg. the 8800GTX will only work in 16x slots so you need a far more expensive board to run a pair of GTX's that a pair of GTS which I think work fine in a 8x slot

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to be honest, if your motherboard can only do SLI or crossfire at x8/x8 or x16/x4 it isn't really worth it, x16/x8 isn't to bad. but i would recommend x16/x16 for sli or crossfire because you'll get the full speed of both cards...

crossfire and sli are a very good way to get a boost cheaply. e.g u could buy 1 card now then in a few months u could buy second card cheaper and get a nice boost...
 
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Never buy SLI or crossfire cards together at the same time. Unless there are the highest of the highend.
Most people use sli or crossfire like Gareth170 said. As you by one first then later down another for a nice boost.
 
Ok thanks for your help so far, I was just confused about one thing, someone told me how with crossfire and SLI you have to buy one master card and one slave? and I didnt get how you can tell on the OCUK website which graphics cards are master and which are slave, is this just for ATI or is it for Nividia aswell? I just didnt want to buy two graphics cards and then find they didnt work.

I know what some of you are saying aswell about it being expensive and I should just buy one but when I do come to buy a new PC I really want to go full out this time. And I really want twice the speed with SLI, so I thought of buying two cards both around £250 each which would obviously be £500, and then have twice the speed, and aslong as I get a motherboard that supports SLI and 16x PCI-E then all will work fine?

Cheers in advance,


SkScotchegg:D
 
You dont need master/slave carfds now. That was only for Crossfire, and the newest ones dont need it.
Just buy an 8800GTX. IMO SLI/crossfire is just a waste. Depends on the Resolution you are gaming on.
 
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SkScotchegg said:
Ok thanks for your help so far, I was just confused about one thing, someone told me how with crossfire and SLI you have to buy one master card and one slave? and I didnt get how you can tell on the OCUK website which graphics cards are master and which are slave, is this just for ATI or is it for Nividia aswell? I just didnt want to buy two graphics cards and then find they didnt work.

I know what some of you are saying aswell about it being expensive and I should just buy one but when I do come to buy a new PC I really want to go full out this time. And I really want twice the speed with SLI, so I thought of buying two cards both around £250 each which would obviously be £500, and then have twice the speed, and aslong as I get a motherboard that supports SLI and 16x PCI-E then all will work fine?

Cheers in advance,


SkScotchegg:D
Click to expand...
some ati cards u need a master card and one slave. but the latest ati cards u don't need a master card and one slave

u would see around 80% in performance boost, maybe 90% in some games...
all u need is a motherboard that is sli or crossfire then u need to buy 2 cards the same e.g 2900xt + 2900xt for crossfire motherboards or 8800gtx + 8800gtx for sli motherboards...

but as i said if your motherboard can only do SLI or crossfire at x8/x8 or x16/x4 it isn't really worth it,

u should try to get a motherboard the can run both cards at x16/x16 or x16/x8..
 
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It just needs specially written drivers to get dual cards working on any motherboard. Just that ATI and Nvidia won't release official drivers for the opposition's hardware to ensure sales of their own (in ATIs case generally sales of Crossfire licensed Intel chipsets).

Jokester
 
Ok well thanks for your comments so far, my only problem now is I dont understand why some members of OCUK are saying dont bother buying two cards and other members are saying I should?

I dont want to waste money, but one guy above said I will see 80-90% increase in performance, so can anyone explain to me if its really worth it buying to Nvidia cards and running them in SLI? or should I just buy one graphics card?

Cheers in advance,


SkScotchegg:D
 
The 80-90% assumes that you're not CPU limited, and generally the only time your not CPU limited these days is if you're running high resolutions (1600x1200 or higher). With a single 8800GTX at lowish resolutions you FPS is so high anyway you won't see a benefit even if you weren't CPU limited.

Jokester
 
it is a waste buying 2 shuddery.

crossfire and sli is good way to get a boost in the future.. buy 1 card now then in a few months or when u need a boost then u could buy second card cheaper
 
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