I can't comment on the power question but I own both boards; I have an i7-920 on the UD3R and an i7 980x on the P6X58D, both overclocked. The UD3R was my first board for a home build and I believe it to be a very forgiving and stable board for those who are new to home building. My only problem with the UD3R is heat management, I really think they could have done a better job on the heat sinks for the X-58, Southbridge and both Vregs. The X-58 and primary Vreg run hotter than I woud like but certainly within norms, putting everything under water cures this but is expensive.
What I really like about the UD3R is the BIOS set up, if you mess up 9 out of 10 times it will fix itself and get you back to a Windows desk top, this is only important if you are into overclocking.
As far as the ASUS board it has many of the qualities of the UD3R with much better heat management, that's about it.
Both support USB3 and SATA3 and both have similar BIOS flashing utilities, both support CrossFireX and SLI, the ASUS board has a few more bells and whistles but I'm still not convinced they are more important than the heat management.
In my opinion if you can spring for the extra $ get the ASUS but you won't go wrong with the Gigabyte.
Regarding the question on 16+2 v/s 8+2 there is a pretty good thread here at Tom's, just enter it in the search window.
Good luck, I really belivev you can't go wrong with either board.
Hi newcomer and welcome to the Tom's hardware forum.
If u want the best, and the price isn't important for your, go for the ASUS, that mobo support SATA III, USB 3.0 and quad-crossfire.
Now, if you don't want spend too much in a mobo, go for the Gigabyte, BUT bear in mind that that mobo don't support USB 3.0 whe you use Crossfire.
Finally, What is phase power? It's easy, means that are 16 phase power for the CPU and 2 phase power for the RAM and north bridge. This is used like a filter for the power, if your go for a quad core (like the i7) is better use a 16 + 2 that a 8 + 2
Thanks for the help everybody. I'm really leaning towards the ASUS now. Would it be as beginner-builder-friendly as the Gigabyte? And do you have any idea if the prices of the ASUS premium will ever fluctuate or preferably go down? I may wait to buy all the parts until I see what everyone thinks of their brand new nvidia GTX470's so I'll be in a holding pattern for a couple weeks.
I had this question earlier and I'm looking at it this way now:
Is it worth the extra money to get the ASUS?
What do you get? USB 3.0, better heat management, and good management of PCIe lanes.
What do you lose? Money.
Chances are I could be happy with the gigabyte and save a few bucks, but there's also a decent chance that down the road in a year or 2 I'm going to be kicking myself over a little investment on the front end. In short, for me, its worth the extra money. You just have to decide how far you're willing to stretch your money...and how much you use USB3.0/SATA III since you're not big on OCing.
Once again I have to agree with saint19. Stick with the ASUS if you can afford it. In my limited experience better heat management + better power management = a longer life for the board and anything attached to it, especially if you are thinking about overclocking. I just think the ASUS is a better OC board simply because of the better heat management.
I shoud put the attention on raid.
My interest is for raid 1 (mirror) with 2 sata 3 hard disks.
Only gigabyte X58A supports the raid 0 and 1 with sata 3 disks.
Asus P6X58D Premium support 2 sata3 disks only in Marvel controller and without raid.
But... I prefere always Asus.
My friends had problem with rams modules.
He asker to the assistence and technicals di not know nothing...