I just upgraded my system to a p8z68-v pro motherboard, and also upgraded my CPU and GPU, and I'm having several strange problems.
Some history... This all began when I was playing around on my prior setup, which was a DWI LGA 775 board. The GPU, a stock cooled radeon HD 4890, had been running fine for about a year, but my system started becoming unstable over a period of weeks, and then suddenly restarted without warning several times, I discovered the GPU was getting up to about 115 C! I cleaned it off dust, but it didn't help the temperature problem. I tried a different slot, same thing, I adjusted air flow, didn't help. I decided to replace the radeon and bought a GTX 580, and a Koolit Omni ALC factory-sealed water cooling setup which consists of a full coverage water block and a 120mm fan/radiator which fits to rear exhaust. The temperature on the new 580GTX was still getting so high it shut itself down. I couldn't figure out what the problem is, so I decided to get a new motherboard and CPU, which brings us to now.
I pulled everything out of the chassis and cleaned everything. Now I have the new motherboard, new CPU (2500k), new 580 GTX with omni ALC cooler, old ram, and my original two western digital HDDs plugged in.
The system boots extremely slowly. From the time I hit he power button, it takes nearly a minute to get through POST. Sometimes the computer will reset up to three times before the display turns on, and there are long periods where the display is "active" but shows a black screen. Windows also takes a very long time to start up, and feels sluggish to use (chrome takes a while to open.) Also, for some reason my internet connection is going at only about 2-5 mbit/sec on internet speed test as compared to the 20mbit/sec I got before, and am still getting on other computers connected to that same wireless router.
Additionally, the GPU is continuing to overheat, even running a windows experience index test gets it up into the 90's C, and at 97 C it auto-shuts-down to protect itself.
I installed windows 7 home premium from a USB drive, because my DVD drive is IDE and i didn't realize when getting this mobo that IDE had gone so out of style, so theres an upgrade there in my future too.
Sorry for this long-winded post, but I'm exhausted atm and thought I should give as much history as possible!
jaquith, you're a genius. I had the problem (I also have the P8Z68-V PRO) of having to wait 1 minute to get past POST (though not the rest of the problems Polyknikes is describing to have). After plugging my PSU DIRECTLY to the wall socket, the waiting time went away (now I hardly have time to see the POST).