Weird problem with An Extreme 4 Z87

Hi Everybody,

I have been having an weird issue with an old board I have, at first I was ready to trough it out but it is bugging me I can't get it solved.

This board boots without a problem and works for hours everything is fine.
If I do a reboot from software or with the restart button on the case it reboots fine.
But when I turn it off (by software or button it does not matter) and try to turn it back on within one hour it the fans of the CPU, CASE and PSU spin for a second and it reboot and keeps doing this.

When I leave it alone and give it another try after a couple of hours it boots and works fine.

I tried every truck in the boot, check if ram is seated, check if it works with one module, removed CPU checked everything and installed CPU again with new cooling paste. Tried with the original Radeon R9 270X and with the integrated IGP. Ran the motherboard only with PSU, RAM and CPU on a cardboard to make sure it was not the board shorting on the acase the problem stays.

At first I had the impression it was related to a Faulty USB port because I wiggled it a bit and then the motherboard booted fien, but that was just a coincidence.

I also tried this:
http://forum.asrock.com/forum_posts.asp?TID=630&title=how-to-clear-cmos-via-battery-removal

But the problem stays, I am getting crazy with this issue, but because the motherboard after a while boots and works fine I am not willing to trough it out yet.

Hope someone can point me in the right direction on what might be causing this weird issue.

Regards,

Ferno.