Asus P7P55D - Freezing at splash screen with Clarkdale only

[RyzenMaster.sys]

I have an Asus P7P55D that came with an i5 750. It works perfectly with the 750 and will boot to a drive as can be seen below.

I want to run this system with an i5 655K instead, however I was getting no POST, so I checked and found the bios version was too old. I flashed the bios from version 0209 to the latest version, 2101.

The board now will display with the 655k, however it freezes at the BIOS splash screen, or occasionally I get the post message.

I have tried booting with no USB devices connected and only a PS2 keyboard, but the system still does not respond to input at this point, and I cannot enter the BIOS. I tried with a known good i3 550 and experienced the exact same result as the 655k.

I tried to flash the bios to an older version however the board will not let me flash a version older than what is on it.

Any ideas?

 

[Ware]

Are you resetting BIOS to default before switching CPU.
Maybe try different RAM or at least more modest speeds, like 1066 or 1333.
DDR3-1866 is well beyond Intel's max for all the CPU's in question, which is 1333.
The QVL's suggest RAM is supported with one CPU but not another.
For example, several modules on the 2.66 Ghz CPU list are missing from the 2.8 Ghz CPU list.
The QVL's don't list any CPU over 2.93 Ghz, and both the 550 and 655K have base frequencies over 3 Ghz.
I know K CPU's are more fun, but other than lacking AES, isn't the quad core 750 better than the dual core 655K in pretty much everything?