ATI Crossfire setup?

cmsamo

I currently have an Abit IP35 XE Pro Mobo, with a Radeon 4870 card.

I want to replace the 4870 with a couple of the newer generation ATI cards in Crossfire configuration.

I know that I need to check my PSU to make sure it can supply power to 2 video cards, but other than that, does anyone have a recommendation for a pair of reasonably priced ATI cards, which will work well with this mobo in Crossfire configuration? I need at least 1gb onboard memory and DirectX10 for each card. DX11 compatibility is of course a bonus

Edit - I guess while I'm at it, I might as well consider a CPU Upgrade. At the moment I've got a Quad Core Q6600 in there...

Nathrak

Radeon 5770's are pretty cheap for 1gb dx11 cards and not too power/bandwidth hungry. You're slightly held back in that your second PCI-E slot is only x4(ver 1.0) for bandwidth but it's not a deal breaker. Just that the higher up the GPU chart you go the more you will be wasting.

Are you using expansion slots for anything else? Newer cards are pretty fat and will be right up against another card in one of the pci slots, blocking some air flow.

I don't know that upgrading cpu would be worth it while keeping the same motherboard.

About the bandwidth of your pci-e slots:

Both are x16 for purpose of what fits in them, but the second is only wired for x4 bandwidth. Both are PCI-E ver 1.0 and are half the speed of ver 2.0 pci-e slots.

Here you can see the performance loss on a 5870 when going to lower speed pci-e slots. Those are ver 2.0 though so your slots would be x8 and x2 which isn't on the chart but imagine it somewhere between x1 and x4.

Sorry if I rambled more than you wanted to know, I just have the same sort of setup and have looked into it somewhat in the past.

cmsamo

Thanks for the info - really useful. I hadn't considered the fact that the slots would be spec'd differently.

Am I better off ignoring Crossfire altogether then, and just getting a single "best in slot" Radeon card? Something like XFX HD 6950?

I noticed as well that yeah, this mobo is pretty dated now, and won't fit any of the new i5 processors.

mts

related to this I know they say you need to have the exact same card for crossfire. Say I have an ATI 5770 made by HIS. Do i need another HIS 5770 or will any 5770 do?

Nathrak

It might be better to go single card for now, and maybe crossfire it in the future on a different motherboard.

Should be fine mixing different brands of 5770 as long as they're the same stats( Like both 1 gb memory). Well I think you could mix a 1gb and 512mb card but it would treat the 1gb card as 512mb so bit silly. So the internet has told me, haven't done it myself!

Moudis

Pick up a good single card for now, Crossfire if you end up needing it later once you have a motherboard with the extra PCI-E 16x slots.

Spend a little extra and get a 5870 or a 6xxx series, it'll last you a good while. I'm running a single 1GB 5870 attached to a Dell U2711 @ 2560x1440, and I've had no problems running current games at max quality.

cmsamo

Ok, Thanks guys. I think I'll go the single card route.

Very tempted to order this right now, for delivery first thing in the morning

Bartholamue

The 6950 is a very fine card (I have it), and with a little tweaking you can make it almost as powerful as a 6970.