Greetings,
Code 55 is a memory error.
***Start here. What BIOS rev are you running, (there are two versions of this board 1.0/1.1) and is there a newer rev that improves memory compatibility? If so, Consider upgrading. >>F5<< absolutely do not flash to F20 its flawed. F21 is ok as well.
If not, continue.
Suggest you load set up defaults with the 6600k CPU installed. Confirm XMP is disabled. Shutdown, disconnect power and install the 7700k. Now try to boot.
If you get the 55 error code again, shut down, disconnect power and remove all RAM except one DIMM. Reconnect power and retest.
If you get POST, you can enter BIOS and enable XMP again. F10 to save and restart. If that works, shut down and add your other DIMM, test again.
I have not looked, but if the ballistix RAM is not on the QVL for your board, it might not be fully compatible. If that's the case, you might have to set memory timings and voltage manually for it to be properly detected. Start with a target of 2133 and see if you can push to 2400.
For comparison, check to see what memory timing are being used with the 6600k installed
The CPU is expecting DDR4-1866/2133, DDR3L-1333/1600 @ 1.35V
With the 7700k the CPU is expecting DDR4-2133/2400, DDR3L-1333/1600 @ 1.35V
Your memory is rated 16-16-16 @ 1.2V
Crucial site says RAM is compatible and supports XMP 2.0. If it won't post, try bumping the voltage to 1.25v with a single DIMM.
