MA790GP-UD4H or MA790X-UD4P

First, take a peek here:
http://www.gigabyte-usa.com/Products/Motherboard/Produc...

So, as you see, they are pretty near the same board...

Differences:
The GP has on-board graphics (which you apparently aren't going to use anyway...)
The PCIe 'laning' is a little different: if you use two GPUs, the GP will keep one at x16, and 'drop' one to x8; the X will drop both to x8 (if you only use one card - doesn't matter, and with that particular graphics card - doesn't matter anyway - you won't 'see' the difference between x16 and x8)...
The X has 8 SATAs (vs 6 for the GP), and comes with an eSATA bracket...
The X supports DDR2-10666, which you can't find, and wouldn't want to pay for if you could...

So it boils down to: two extra SATA ports, and an eSATA bracket probably worth the $10 difference by itself, if you have a use for it...

Wow thank you for the input i will definately go with the X it is ten cheaper and looks like its got the options to have also. one more thing do you know anything about crossfire with onboard ? does it help any For the GP

Ahhh - difficult subject, fraught with unknowns...

First point: "ATI Hybrid CrossFireX™ Technology is only supported with Windows Vista® operating system, and is not available with Windows® XP operating system." (but a little research says it is also supported under Windows 7...)

Here's a fairly confusing compatibility chart:
http://game.amd.com/us-en/content/images/crossfirex/CF_...

and a list of compatible cards/MOBOs:
http://game.amd.com/us-en/crossfire_certified.aspx?cat=...
(the MOBO is there [note that there are two Gigabyte entries with two different charts]; that graphics card is not, though several 4670s are, and several HIS cards are - so my guess is that it's just not been tested)

and you might want to spend some time poking about here:
http://forums.amd.com/game/categories.cfm?catid=262&for...
just to get a feel for how people are doing with it...

Overall, I wouldn't buy a setup that's not on their list:
http://game.amd.com/us-en/crossfirex_configurations.asp...
based on expectations of this feature working, but I would 'risk it', and simply hope that a 'neat feature' might be available!

Good luck!

Bill