SLI / CrossFire FAQs

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devilstenor89

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May 17, 2012
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This thread is so big, the answer to my question may already be answered, so I apologize if this is a repeat question.

I am currently in the process of ordering parts for building my own computer. I would like to use Crossfire-X to link two graphics cards to use together, but the cards I have picked lack the typical connector for the bridge on the top of the cards.

My reason for wanting to Crossfire these cards is to support three (3) monitors. I know that I do not have to Crossfire them to support the three monitors, but I would like to try it so if I ever need to link two graphics cards in the future I will have the experience.

I want to know if these cards do not need the bridge in order to function in Crossfire-X? I have found some info that says that lower end cards do not need the bridge because the PCIe bus has the bandwidth now to support the Crossfire-X technology without the bridge, unlike previous versions of the PCIe bus.

Parts:
- 2x Sapphire 100292DDR3L Radeon HD 5450 Video Card
http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=149617&Sku=A271-5456
- GIGABYTE GA-Z68AP-D3 Intel Z68 Motherboard
http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=1165562&Sku=G452-1047

Thanks for any words of advice concerning this issue.
 

oxford373

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Jun 22, 2009
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i tried once tow ati 4850 512mb in cross fire mode with core i7-920 as toms hardware recommended, it was horrible experience because 1)you cant max-out games graphics details because you are limited to 512mb frame buffer 2) almost all ati 4850 was equipped with very bad cooling system and weren't designed for crossfire ,one 4850 on its own go as hot as 94c, and when you play on CF mode it reach 107c and when that happen the games slow down, and you also need to update the drivers every month with every new game to make sure that both cards are working(without latest drivers some new games wont work on CF mode) after that i will never try CF OR SLI again
 


GTX670 blower types (MSI) in an Asus Crosshair Formula V.

I already have one and it's such a quiet and cool card that is begging for a partner, hahaha.

Cheers!
 

Maziar

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Should work fine.
 

skeleton68

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Apr 25, 2012
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I set up 2 6870 cards in crossfire and my games FPS sat at 60 on high settings (MW3, BF3) but I was lagging for some reason. Took the second card out and stopped lagging. So sometimes Crossfire does affect performance.
 

master_nz

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Feb 12, 2012
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is the second card an exact match of the first.?
EXACT MATCH specs wise at least...
Yes. They are both GTX 670 EVGA cards. I'm currently overclocking both at the same time using precision and it seems to be working fine.
 

michaelb59

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Oct 6, 2009
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Thanks Maziar: Very informative, lucid, comprehensive and easily understood. Answered my question, saving me the trouble of posting it.
 

Maziar

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Moderator

I'm glad it helped ! Soon,I'm going to update it again with more info
 

beringela001

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Oct 14, 2012
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Im not sure if this was answered already, but I read that you have to have the same family of cards to be able to SLI them.

So my question is: Will a GTX465 SLI with a GTX550 TI??

Apart from the difference on Cuda cores everything else seem to be pretty equal or close to each other.

PS.: Sorry if its a dumb question. Just new to this SLI thing.
 

nukemaster

Titan
Moderator

In the case of the 5XXX cards it was

5 series
Then performance numbers(Think of 7 as mid end 8 as high and 9 as dual gpu. Everything lower was low end gaming or media). This is the most simple way to explain it.

So the 5870 was the replacement/upgrade for a 4870(in a way of speaking), While a 5450 would be MUCH worse then a 4850 and is a replacement for the 4350/4550

The 5970 was 2 5870's down-clocked(to reduce power and heat) on one card.

AMD does not seem to keep the numbers the same on all cards.

A 6870 is not actually a replacement/upgrade for a 5870(as it was just slightly slower). The 6970(its a single gpu card) is and even it was not "that" much faster.

In the 6XXX cards the dual cards are NOT denoted with a 6X9X any more either the dual card is the 6990.

The 6750 and 6770 are just the re-badged 5750 and 5770 card. They can even be put in crossfire together.

So in general, look at the series as the first number then performance as the last numbers and read reviews if you want to know how a card will perform.


As far as I know, On the Nvidia side, you have to have the same cards for it to work properly.
 

krayzier1

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Oct 15, 2012
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XFX Radeon HD 7970 black is compatible with the other in its range HD 7970 for CF?
seems your saying that as long as the GDDR is same and the speed is aits full steam ahead ? am i right ?...and how will this play out for the OC on the black edition ?
 

officerkrc

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Nov 7, 2012
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if this has already been addressed I am sorry.. I just need some help now..

I have a problem.. I have 600 bucks worth of cards and they don't perform.. I have two MSI N560GTX-Ti Twin Frozr II 2GD5/OC.. with 2GB.. I have a i-7 2600K CPU and a GIGABYTE GA-Z68XP-UD3 motherboard.. Running 16 GB Ram (2X Crucial Ballistix Sport 8GB. I also am running two Chronos SSD as well as 2 1 TB WD sata 6 drives.. I have a 680 watt APEVIA ATX-AS680W-BL 680W.

I can run one card and it crushes the two in SLI.. Can anyone tell me why? Seems afterburner telles me second card has 0% GPU use..
 

krayzier1

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Oct 15, 2012
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can you crossfire HIS Radeon HD 7970 X2 with r7970 black edition? are they still in the same family as there 2xs?
 

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