In that case it sounds like it could well be the CPU that is problematic. If you purchased both the motherboard and CPU from the same retailer then I would suggest returning them for investigation.
CPU is bought different time than motherboard and from different retailer so thats not really option and really dont think it cpu in fault here anyway. If you google "EX58 UD5 cold boot problem" you get loads of hits, seems that this is really common problem with this board. Some peoples even have this same problem with newer X58A-UD3 gigabyte board like this guy ->
http://youtu.be/PSsDqdjDTfg?hd=1Also as i allready said these problems started at the same moment when changed to this mobo from P6T SE, with that mobo and even with MSI X58 i had before that all was problem free.
It could be that there is some setting at bios that causes chipset to reset itself ( what is most likely the cause of that boot loop ) when cpu is overclocked/settings changed but no idea what it could be. I also noticed that with differen blck it boots different amount, example with 160blck it boots 2 times, but with 180 blck+ 3 times.
This is just really frustrating as pc is totally stable even at 4GHz (21x191) but that boot thing is really annoying.