As I replied in your other thread, I assume you are referring to PCI Express 3.0 - http://en.wikipedia.org/wiki/PCIe#PCI_Express_3.0 it effectively doubles the PCIe lane speeds. It's release keeps getting pushed back; my best "guess" is late Q4 2010 or Q1 2011.
ASUS doesnt touch PCI slot ? i saw that GIA when use es USB 3.0 or SATA 3 , PCI e Decrease to 8X , so what about the time that some person ONLY PLAY games , in that time he doesnt use USB 3.0 , what would happen PCI will be 16X or 8x on GIGA mobo ?
First, I personally won't choose either MOBO. My preference for ANY Intel is EVGA, and then ASUS, next MSI and dead last Gigabyte. And I did say, "ASUS has less of a problem managing heat than Gigabyte" - so I don't know WHAT I'm MISSING???!
All of these MOBO are PCIe 2.0, exception EVGA P55 FTW SLI | 132-LF-E657-KR PCIe 2.1.
Out of the mix I only can recommend the ASUS P7P55D-E Pro, and after that then neither of the (2) MOBOs would I recommend. I know you're making a regrettable mistake over $30 USD.
Personally, I like the EVGA P55 FTW SLI | 132-LF-E657-KR, but I'd settle with the ASUS P7P55D-E Pro. I would NOT build off either the ASUS P7P55D-E or GA-P55A-UD3. Gigabyte has known H/W issues with the Intel chipsets. I see 10:1 Gigabyte unresolvable problems to ASUS in this forum.
Further, PCIe "temps" is an non-issue with either Gigabyte or ASUS; ASUS overall runs cooler.
PCIe 2.x vs PCIe 3.x - According to you, and the $30 decision, I seriously doubt that you would spend the extra $50+ to $100 for the PCIe 3.x, and if you did with (1) or (2) CF mid-level GPUs then you'd be totally wasting your $!