I'm a little concerned because I have 2 GTX 480's on the way, and they run hot...
I know they're meant to run hot though, and I have a large case with ample cooling... You don't think heat should be a problem? Most likely will not be OC'ing them... seeing as it's already overkill, I just don't want to buy a PC for a while.
I'm still not convinced that you couldn't run it in a 16x, 0x, 16x config.
I'll get it in 2 days, and report back.
Okay, I have some bad news for you. I have that same exact board. When I first got it I bought 2 GTX 285's to run in SLI, and I had the same exact idea as you, run them in the first and third slots. I had a power supply that could easily handle a pair of GTX 285's, and I connected the SLI bridge and downloaded the newest drivers, everything was done correctly, but running those cards in 1 and 3 caused HORRIBLE stuttering and made games totally unplayable. I thought maybe one of my cards was bad, but when I changed the configuration to slots 1 and 2, the cards ran beautifully.
I contacted EVGA tech support and they told me that, indeed, when using 2 cards this board is designed for them to run in slots 1 and 2.
I'm very curious to see if slots 1 and 3 work for you, because if they do, then maybe I have a defective slot 3. But, you will probably run into the same problem I did, in which case you might have to suffer with a slot 1 + 2 setup like me.
How do I like this board overall? Hmm, well, it has a few good and bad points, other than the GPU slot issue I had.
On the negative side, this board has a well-known issue of "disappearing RAM". Google E758 3.99 and you'll get a lot of forum topics regarding this issue. Basically, there are many users who install 6 GB of RAM only to have 3.99 shown as usable by the computer. Or, if 8 GB is installed 6 shows up, etc. I myself have 12 GB installed (overkill, I know), and although all 12 GB show up as usable, if I overclock the RAM past 1333 Mhz my computer only detects 8 GB of RAM (even though my RAM is rated for 1600 Mhz). Now, I made the mistake of not checking EVGA's site for compatible RAM (they have a list on their site for each MB), and the type I bought was not on the list. I don't need to clock mine past 1333, so it isn't really an issue, but I would suggest checking the list before you buy your RAM, if you haven't already.
On the positive side, the board overclocks the CPU like a dream. I have my i7 clocked to 3.6 Ghz 24/7 on stock voltages, runs totally stable. My 1333 Mhz ceiling for the RAM limits my overclock to around 4.2 Ghz for the CPU, but this doesn't bother me because I see no need to ever keep my CPU at that level based on performance gained vs. power usage, etc.
Also, EVGA's tech support line is available 24/7 and they are knowledgeable, helpful people. I called at 4 AM on a Sunday morning, and I got a real, English speaking person, which is pretty hard to say about any company.
I had read a few complaints about memory, so we'll see how it goes.
I also read CPU OC is extremely easy, so it's nice to hear from someone directly, I have a i7 930 on the way.
I don't know if you knew this already or if this isn't related at all, but its worth mentioning. I heard the board doesn't like higher than a 10x memory multiplier (it may not even have the option, I don't know), so maybe if you used a higher BLCK to get your ram at 1600 or whatever yours is rated at, it will make a difference?
Just a thought.
Looking forward to great support, even more so a nice warranty. =]