Warning to everybody!!! The latest DP55KG BIOS update KG3456P from 21th May damaged my mainboard. Flash process has processed correctly - everything is flashed as should be, than after restart computer is stuck in the BIOS post phase 21 before a graphics card is initialized so no image exists . BIOS distaster recovery from CD doesn't work (using mainboard switch) it stucks at the BIOS post phase 26 with no image. Both post codes 0x21 and 0x26 mean memory problem. I use very good memory paired modules kingston KVR1333D3N9K2/4GB and before this update they worked correctly.
BIOS 3456 is an old BIOS........almost a year old, dated 08-21-2009, not May 21st, 2010. Since then, BIOS 3712, 4905 and 5531 have been released. FYI, I am also experiencing Post 21 errors as well, but in my case they are intermittent. It started a couple of months ago, and is still occurring with BIOS (4905), although I do not know if it is BIOS related or defective hardware at this point. The IDCC stopped working as well and my keboard has failed occasionally on boot. This is the most unreliable Motherboard have ever purchased, and I do not even overclock.