[CP5670]

Slight preformance? Check the benchmarks:
PCI Express Scaling Analysis

It's a large hit between x4 and x8 to say the least. I would like to see a comparison SLI/xFire of dual x8 and x16/x4. You'd think the latter has better preformance, though the former should be better (as its barley a difference between x8 and x16).

Interesting article. It looks like the performance hit on an 8800 is a lot bigger than I thought. However, a lot of it has to do with the particular cards and games they chose to use. COD2 uses especially large textures (probably larger than any other recent game) and the 320MB card is just swapping to the main memory a lot, while the 512MB one doesn't need to and shows a fairly minimal decrease. The hit on a 768MB GTX will be even smaller. The professional 3D apps also demand larger amounts of memory than games, so the performance hit is even greater there as you would expect.

Finally, for whatever reason, the XFX 8800 GTX card doesn't come with molex->PCI-E adapters; they include a slip of paper that says that they specifically do not support such contrivances, and urge users to use dedicated PCI-E power lines from SLI-ready PSUs. Whatever.

It's funny that they say that, since the 8800GTX actually uses slightly less power than a few of the previous generation cards. In any case, you can always buy those adapters separately for a couple of dollars.

[Sandwich]

Uhm, perhaps it may make use of less power, but the power requirements are higher. After all, it's the first card to require 2 PCI-E power cables (75w ea. IIRC) in addition to however many watts the PCI-E slot supplies.

[CP5670]

Yeah, but that was somewhat overkill on Nvidia's part, similar to the AGP 6800 ultra. See this and this. It may have been done to help with card manufacturer-sanctioned overclocks in the future, as the 8800 has quite a bit of headroom.

[Descenterace]

All this hassle with compatibility is why I just upgrade the whole machine if that's the logical upgrade path. If I can't afford it, I wait until I can.
The other factor is that, when I decide to upgrade one thing, I generally think 'I might as well upgrade this thing at the same time' and it all kind of snowballs...

Which is why my recent change of case turned into a complete revamp, although the old graphics card's death probably had something to do with it, too.

[Bob-san]

You had an excellent choice for the motherboard... Anandtech just (like the other day) did a review about the Asus P5N32-E SLI Plus board...

http://anandtech.com/mb/showdoc.aspx?i=2958&p=1

[Sandwich]

Yeah, I saw that just the other day; I love RSS feeds.