The x58 motherboards aren't that expensive when you consider they support both sli and crossfire.
It won't matter if you don't intend to use both SLI and crossfire.
Though, if you wanted to use two Nvidia GPU's, you could just get a 295. Then it wouldn't matter if the board used a crossfire-only chipset.
If you're not intending to spend top dollar to have the absolute best, then
a) you probably won't be getting 4 GPU's from either ATI or Nvidia.
b) you would probably go with a Core 2 or Phenom II system (a lot of people won't buy a quad, because they don't think they'll find it useful)
There are 780a am2+ motherboards that cost nearly as much as comprable x58.
Yes, I don't know why they cost that much, but I think they're more expensive than they should be. 790GX boards can be had for ~$100-$110.
I didn't deny it would be expensive, but the AM3 DDR3 support is meh at best. The speed cap is pretty low and its only dual channel.
I'm pretty sure AMD gave board makers have the option of having a higher RAM divider for AM3.
Besides, triple channel isn't even useful to i7. From what I've seen, it gets 0-2.5% performance increase compared to dual channel.
So if you did want to go for an i7 system, you could easily just use 2 or 4 sticks of DDR3, instead of 3 or 6, and you wouldn't notice the difference.
The improvement over DDR2 is negligible.
I agree with this though. The performance increase from DDR2 to DDR3 on AM3 chips is about ~5%, and the prices of DDR3 still don't make it worth it.
Plus, AM2+ 790GX boards are widely available and cheap.
So if you want DDR3 performance that actually makes a difference then yes you would need an i7 rig.
Actually, I think the reason i7's don't support DDR2, is because of the timing of the release, along with the fact that it is intel's first IMC.
It wouldn't make sense for them to spend extra R&D on their completely new IMC to add DDR2 support, when DDR2 was on the way to being replaced by DDR3.
AMD still has some bugs they need to iron out.
AFAIK there's only one bug with AMD's DDR3 support, and it's nothing to do with the hardware; it's a software issue which won't allow it to work with more than one DDR3 DIMM per channel. That will be fixed with a BIOS upgrade (if it hasn't already). And this fix isn't something that will degrade performance.
But I still think cost-wise its best for him to get his AM3 chip with an AM2+ mobo. That way he can upgrade when the DDR3 support catches up and he can save money now.
Yes, I agree with this. While DDR3 is getting closer to DDR2 prices, it isn't there yet. And the choice of AM3 boards isn't that great yet either.
I've got no plans to upgrade from my AM2+ board, as long as AM3 chips still work in it, and the memory bandwidth and latency is fast enough to not bottleneck it (I'm running 8GB DDR2-1066 @ 5-5-5-15)