ATI Crossfire Compatibility Question

[dwmcc]

Hello All, and thanks in advance for any help provided.

I built my own gaming computer last year, and it's been working like a champ! I do think it's about time to do some upgrades, though and I have a few questions:

In my computer, I have:

-- GIGABYTE GA-MA790XT-UD4P AM3 DDR3 AMD 790X ATX AMD mobo in my computer (link), and I believe it has two PCIE slots (one x16 and one x8, but I'm not sure on this).

--XFX HD-487A-ZHDC Radeon HD 4870 1GB XXX 256-bit GDDR5 PCI Express 2.0 x16 HDCP Ready CrossFire Supported Video Card (link) in my computer, in the PCIE x16 slot.


Finally, I'm looking to purchase a HIS H585FN1GD Radeon HD 5850 (Cypress Pro) 1GB 256-bit GDDR5 PCI Express 2.1 x16 HDCP Ready CrossFireX Support Video Card w/ Eyefinity video card (link)

I'm wondering three things:

1. Are there really two PCIE slots in my mobo?
2. Will these two cards both work in the PCIE slots in my mobo?
3. Will these cards work together with crossfire? (main question)

Thanks so much for any help you can provide.
-iTALIO (dwmcc)

 

[Aastii]

1. Yes, there are 2 PCIe x16 lanes and you can run crossfire

2. They will both work at the same time for multi monitor support, BUT

3. not in crossfire.

With ATi cards, if the first 2 numbers match, they will work together in crossfire, for instance a 5850 and a 5870 will work, a 5750 and a 5770 will work, a 4850 and a 4870 will work etc. There is an exception to this rule when it comes to the 5970. A Radeon HD 5970 is 2 trimmed down 5870 cores on a single PCB, so a 5970 can be put in crossfire with any 58xx cards

Another, probably better, option would be to sell your 4870 and go for a single 5870. It will be about on parr with performance, but will give you better upgradability, use less power, take up less space, and produce less heat. Though if you were to do that, what power supply will you be using? A 5870 draws a little more power (~20-30W) than the 4870 does, but that little difference could cause massive problems if you are on a low end unit, or already pushing your power supply as it is

 

[iPwn]

1. Are there really two PCIE slots in my mobo?

Yes, it's possible.

2. Will these two cards both work in the PCIE slots in my mobo?

Yes.

3. Will these cards work together with crossfire? (main question)

No, the highest card you cab CrossFire with your existing card is a 4870 X2.
See here.