Hello!
I've got the same problem, but not after installing, I'm just trying to install this, and still can't find a solution.

EFI enhanced bootloader build: ToH
Using SMBIOS table found at 0x000f1be0
Using ACPI RSDP revision 0 found at 0x000f7750
Hey we are going backwards! -> , restarting timing
Hey we are going backwards! -> , restarting timing

Calibation failed with 2 attempts

I have asus p5vd2-x motherboard. I have found an option to turn off acpi support but it's gray, so that I can't disable it. I've read somewhere over the net that it's due to Core 2 Duo E6300 processor which I own. I've tried also booting with "platform=X86PC", "acpi=off", "-v -x cpus=1" etc. but I couldn get it work. I've also tried just waiting about 1h in hope of getting it work... ofcourse it didn't help to. Can anybody help me? I am desperated

p.s. tried with leo4all 10.5.2 and Kalyway 10.5.1