Thanks for suggestions and manual link. I'll give the cmos a clear just soon as done formatting a 1tb micro sd to ntsf (25% there).
Hard to believe how fast a 240gb ssd fills up for a home user.
When i switched out an i5 4th g for an i7 4th g , in another unit, it booted right up so no i hadn't tried the cmos.
Thanks again.
It depends on the exact CPUs.
In this case, the replacement CPU was from the Haswell refresh and was released about a year after your original CPU. That can be a problem without a BIOS update. This is a frequently encountered issue with the consumer CPUs you reference: people upgrading from i5-4670k to i7-4770k would usually have no issues while i5-4670k to i7-4790k would require a BIOS update for the Devil's Canyon chips.