I just bought a machine with P8P67 LE. When I turn on the machine, the fans would spin for about 3 seconds, then they would stop, then after some moment, they would start again and boot normally. Everything else is normal other than this. No crash and no hang with long hours of 3D gaming. This happens with and without overclocking.
This is a common issue, and there is no consistent solution. Update to the newest BIOS for your board to see if they have fixed it yet. If not, a future BIOS update will do it -- you just have to wait for it to come out.
This is common (and normal) if you are turning the PSU power switch from OFF to ON but it shouldn't happen if you use the normal case power switch.
(It's a PSU issue if the only fans immediately starting up that first time are DIRECTLY connected to the PSU and not through the motherboard. The PSU is starting up, probably running a diagnostic then rebooting before working normal.)
Things to do:
1) check for BIOS update
2) double-check all internal connections
It doesn't sound like something to worry about though.
It is a very common mainboard issue with Sandy Bridge systems, that can only reliably be solved with a BIOS update. Other supposed remedies don't work consistently.
You don't need to check all internal connections.
My ASRock board (both the B2 and B3 versions) did this until the last BIOS update from a few days ago. That fixed it right up. You just need to check and see if the newest BIOS fixes it, and be patient if it doesn't. This isn't harming your system in any way, so there's nothing to worry about.
Thanks all, I just tested again, seems that it happens only when overclocking. Need more rebooting to be sure. The BIOS had already been updated to the latest at day 1 of purchase. I asked ASUS technical support as well, waiting for their reply.
The ASUS technical support did not help much. At first, he thought it was a cannot-boot problem. Then, he explained that overclocking may cause unstable system, which again was not my case. Guess I will have to keep trying new BIOS version.