Some info on the 790i:
The 790i is a new is the first new chipset from nvidia in several years. The 780i is just the 680i chipset with a 3rd slot for 3-way sli. The new chipset has several new features that make SLI scale better. I have seen ~1000 point increase in 3dmark06 using close to identical conditions. There are reviews out there that show a performance boost in most games ranging from 2 fps - 15+fps due only to a board change.
Here is an Anandtech
article on the 790i architecture.
As far as DDR3 goes, it has become so much cheaper right now and the performance boost it offers in memory intensive games and applications is quite good.
I did have problems with this board with early BIOS's, but the newer ones have been very stable. I have had luck with Teem Xtreem which I got from newegg(they are out now) and have been successfully using GSkill HZ's which newegg has for $154.99
and are quite a bit faster than ddr2 offerings. There are other decent kits available at around $80 but aren't as fast. Besides, newegg is pretty good about ram replacement if it is bad.
Other than the memory, the board had been very good. Very straight forward overclocking and fun to play with and quite stable.
Lastly the 790i is a better overclocker than the 780i. not that you would need it but I hit 585 FSB, and others have hit high 500's and into 600's.
Take a look at our 790i thread if you want more people's opinions of the board overclocking and messing with it.
-sergeEdited by SergeRY - 7/8/08 at 6:51pm