Difference between motherboards?

[JEMC]

Slimebeast said:

JEMC said:

For starters, the 2 boards with the 970 chipset only have 1 electrical x16 PCIE, so none of them are good if you plan to go with 2 graphic cards. And they have differences in the Audio chip and number of USB ports, as well as one having  connections for both PS/2 keyboard and mouse while the other only has room for one.

Check the comparison http://www.gigabyte.us/products/comparison/list.aspx?ck=2&pids=4717,4591

Regarding the 990, the 990FXA has 2 x16 PCIE slots while the 990XA has one x16 PCIE and one x8 PCIE, as well as having an extra chipset that gives it another 2 6Gb/s SATA ports... on the back.

Check the comparison: http://www.gigabyte.us/products/comparison/list.aspx?ck=2&pids=4672,3901

And here, the 4 cards compared: http://www.gigabyte.us/products/comparison/list.aspx?ck=2&pids=4717,4591,4672,3901

To summarize, get one of the 990 mobos if you want to go with 2 cards as having 2x16 or 1x16+1x8 will have little effect.

So the cheaper 990 is good enuff to run two R9 290s in Crossfire? The weaker GPU slot will not bring down the perfromance?

Btw, can I combine a R9 290 with a next gen AMD card (a future 380 or something) or do they still need to be two cards that are exactly the same?

You'll be perfectly fine with that setup. It's an old article but

http://hardocp.com/article/2010/08/16/sli_cfx_pcie_bandwidth_perf_x16x16_vs_x16x8/1

Gameplay performance can be summed up very easily and directly. We experienced no differences in the gameplay experience between x16/x16 SLI or CFX compared to x16/x8 SLI or CFX. There were measurable differences, differences that some people might pick apart and declare a clear "winner," but we don't see it this way at all. For gamers, the differences are so minuscule that the delta simply does not matter.

As for your other question, I have no idea. The HD7xxx series can be mixed with the Rx 2x0 series because they are the same cards, just rebadged with another name. But when it comes to the next series of cards, they will probably use a new architecture so it's unknown if both kinds of cards will be able to work together.

But even if that they don'0t work together, by then you'll be able to get another 290 far cheaper than now .