Ok yes another Thread about SLI ..

Ok what i'm thinking is this .I all ready have ATI 5870 hd in my computer with 700 watt power supply that is pretty new tbh but not sli ,And was thinking is it worth me getting another card to make it sli ,But the problem is i would need to get SLI power supply as well ,

Or would it be better for me to sell my ATI 5870 HD and just get ATI 6970 HD DUAL GPU .And that way i would not need to buy another power supply ? .


And whats the benerfits of the two card ( 5870 SLI VS 6970 DUAL GPU )

cheers

You could stick ten 5870's in and you would never achieve SLI

You meant to say Crossfire!

100% certain you'll need an SLI power Supply as it wont come with the proper ammount of cables i.e 8pin +6pin x2 also id get abit more Powerful one not too sure how much Crossfired 5870's draw at full load tho..

and im sure you mean the 5970 right? not the 6970 thats a single GPU card.

- Bayk

Hi there,

I think you are think of "CrossfireX", SLI only applies to Nvidia cards.

As for your question, with the price of a second brand-new HD 5870 currently sitting at £150, then running two of these cards together is Crossfire is a pretty nice value, high performance graphics setup.

That said, to run CrossfireX you will not only need a quality power supply (with four PCIE power connections) but also a motherboard that fully supports crossfireX. May I ask what exact make and model motherboard and PSU you are using?

Also, the HD 6970 is a single GPU card (it is the current top-end AMD single GPU card), it is the 6990 that is a dual-GPU card.

Hi again thanks for all your replys and yes i was thinking SLI due the power supply as you never see the for sale as crossfire suported , And I
was along time user of invidia and was thinking along the same line and not crossfire so sorry for that confustion ,

Ok MOBO is P5Q PRO TURBO it as got crossfire on it so will be fine ,All so i checked on the card 6970 and yes it as one chip but dual graphics engines in one chip ,so dont that mean two gpu's ??? just like cpu as more than one core .this is the info from overclockers specs (( The ATI Radeon HD 6970 uses a new GPU architecture from AMD which features dual graphics engines in one chip ))

I forgot to had the power supply info that is 700w coolermaster pro silent

Aye, that motherboard will be fine - it does crossfireX using the two main graphics ports at PCI-E x8/x8 speeds.

As for the "Dual graphics engines" - I agree this is a bit confusing as it refers to the internal architecture of the GPU: SIMD engine blocks (large blocks made up of many SIMD engines) - however this is all on one GPU.

As for SLI certified power supplies (or Crossfire certified)- this is also a bit confusing as it really depends on what particular graphics card you are running in crossfire or SLI whether the PSU can handle it.

If you can tell us the make and model of your existing PSU then we should be able to tell you whether it can handle two 5870s in crossfire (if you can't recall, then if you open the case and look for the sticker on the side of the PSU you should see this info).

May I ask what the rest of the spec of your system is? (this will allow us to work out the maximum power draw of your system and estimate whether anything will be bottlenecking the performance of your system if you install a second 5870).

700w coolermaster pro silent ,
Cpu is Q9550
Ram is DDR6400 .

mastering3d said:

700w coolermaster pro silent ,
Cpu is Q9550
Ram is DDR6400 .

Click to expand...

Excellent.

In that case I would go with that second 5870 - your system can easily handle it and it will give you a nice boost in performance.

cmndr_andi said:

Excellent.

In that case I would go with that second 5870 - your system can easily handle it and it will give you a nice boost in performance.

Click to expand...

What would you say would be a good power supply to get ??

You could try your current PSU with two 5870s in crossfire, you will need to use two of the molex to 6pin adapters - but looking at this review it will be pretty close at full load.

If you would feel more confident with a new PSU, then this one will certianly handle it (here is a review).

cmndr_andi said:

You could try your current PSU with two 5870s in crossfire, you will need to use two of the molex to 6pin adapters - but looking at this review it will be pretty close at full load.

If you would feel more confident with a new PSU, then this one will certianly handle it (here is a review).

Click to expand...

but the one i have is not crossfire .

The power supply has nothing to do with your ability to CrossFire your graphics card...

mastering3d said:

but the one i have is not crossfire .

Click to expand...

It doesn't need to say "crossfire" on it to mean that it will do crossfire - that is just marketing - same with "SLI certified" PSUs. So long as it has the correct connectors and provides enough stable power to the cards on the 12V rail (yours is rated at 50A I believe) then it will work.

That said, your PSU is rated at 700W and has two 6+2 PCIE power connections, for dual HD 5870s the maximum power draw seems to be around 670W and requires four 6 pin PCIE connections. You can get round the connector issue by using two of these, but running two 5870 cards together will bring your PSU close to it's maximum under full load.

cmndr_andi said:

It doesn't need to say "crossfire" on it to mean that it will do crossfire - that is just marketing - same with "SLI certified" PSUs. So long as it has the correct connectors and provides enough stable power to the cards on the 12V rail (yours is rated at 50A I believe) then it will work.

That said, your PSU is rated at 700W and has two 6+2 PCIE power connections, for dual HD 5870s the maximum power draw seems to be around 670W and requires four 6 pin PCIE connections. You can get round the connector issue by using two of these, but running two 5870 cards together will bring your PSU close to it's maximum under full load.

Click to expand...

wow thank you so much you have been of real great help to me .if there was grading for help on here out of ten you would get full ten from me cheers man

if i need more help ill pop back in ..

Hi again one other thing thats been on my mind if i was to use or try and use my power supply with them cables ,What kind of config would i be looking to do from the PS ..

mastering3d said:

Hi again one other thing thats been on my mind if i was to use or try and use my power supply with them cables ,What kind of config would i be looking to do from the PS ..

Click to expand...

Well I would suggest plugging one of the two standard 6pin PCIE power connections from the PSU into each card (these cables are 6+2 connections, just uncouple the +2 part from the main connector and leave it un-connected). Then with each of the two adapter cables, connect the four-pin ends to a molex four-pin connector coming out of the PSU, then plug the 6pin end into the remaining power connection on the graphics card.

It may get a bit messy with cables- but this is the way when running two high-power graphics cards and well worth it imho.

Can I just confirm, this is your PSU, right?

From reading the above you still seem confused about the 6970.

It's a single GPU. I don't know what "but dual graphics engines in one chip" is supposed to mean.

Crossfire 5870's are much better than a single 6970 except possibly at extreme resolutions:

http://www.anandtech.com/bench/Product/300?vs=292

cmndr_andi said:

Well I would suggest plugging one of the two standard 6pin PCIE power connections from the PSU into each card (these cables are 6+2 connections, just uncouple the +2 part from the main connector and leave it un-connected). Then with each of the two adapter cables, connect the four-pin ends to a molex four-pin connector coming out of the PSU, then plug the 6pin end into the remaining power connection on the graphics card.

It may get a bit messy with cables- but this is the way when running two high-power graphics cards and well worth it imho.

Can I just confirm, this is your PSU, right?

Click to expand...

yes thats the Psu

All so do i need to use two rails on the psu or can i run both PCI Express 6-Pin to 4-Pin Power Adaptor on one rail ?

Surveyor said:

From reading the above you still seem confused about the 6970.

It's a single GPU. I don't know what "but dual graphics engines in one chip" is supposed to mean.

Crossfire 5870's are much better than a single 6970 except possibly at extreme resolutions:

http://www.anandtech.com/bench/Product/300?vs=292

Click to expand...

Ah yes cheers

Ok got the card today after ordering to find that i had two power cables in with the card so got another two now ah well nvm .

But heres the thing ,I installed the card and both crossfire connectors to the cards and switch them on in the drivers ,but then run the games that i play to find that i still have the same fps for all games that i play, Before having the cards installed .So i was like emm ok took the new card back out and tryed the games again to make sure that i was not crazy and the fps was the same ,And yes all games have same fps with single card or with crossfire ,Some thing must be wrong some where but i cant work out what that could be ,Drivers that i have install are 11.4 the newest ones that just came out i even installed the profile thats on there site in the hope that would fix the problem ,But know still the same fps just £150+ down and still have the same fps .please some one what am i doing wrong how can i be getting the same fps with only one card out of .