Here are my specs (running F6 bios):

* Intel Core i7 920 D0 Stepping (SLBEJ) 2.66Ghz (Nehalem) (Socket LGA1366)
* Gigabyte GA-EX58-UD3R Intel X58 (Socket 1366) PCI-Express DDR3 Motherboard
* XFX Nvidia GTX 260 core 216
* OCZ Gold 6GB (3x2GB) DDR3 PC3-12800C8 (1600MHz) Tri-Channel
* Corsair HX 750W ATX Modular SLI Compliant Power Supply
* Titan TTC-NK85TZ Fenrir CPU Cooler
* 2x400GB Western Digital in raid 0
* 1x500GB Hitachi Deskstar

This thread details my problem precisely (for the UD5 but applies to UD3R too):

GA-EX58-UD5 and G.Skill DDR3-1600 6GB issue?

Does the beta bios fix this? Where can I find a changelog for the beta bios?

The issue is that the machine double boots when mains power is lost before switching on.

It turns on for about 2 secs, turns off, then about 3 secs later powers on as usual.

I have a light overclock to 3Ghz.

This is putting unecessary strain on components - why has this issue not been fixed? Is it a capacitor issue?