Switching from a MacBook Pro mid 2012 i5 to a i7 weird issues?

So I have a MacBook Pro mid 2012 13” (1) with the i5 processor 16gb of ram and a Samsung 860 evo it runs well on Sonoma.

I found a “parts” MacBook Pro mid 2012 13” (2) with a i7 processor in it for $70, turns out this thing is extremely nice, needs a battery, I installed a blank ssd and installed Monterey, everything works flawless as far as I can tell, I can’t find a single function that doesn’t work.

I swapped ram and hard drives from the i5 (1) to the i7 (2) ran OCLP, saying they are both 9,2 computers. I also re did the cpu thermal paste. It boots up way faster, but I’m getting some lagging and activity monitor is bouncing around a lot ? Could something be wrong on the motherboard? I’m going to update Sonoma from 14.4 to 14.7 to see if that helps.

In this process I swapped the ram and ssd with Monterey from the i7 (2) into the i5 (1) and it works flawless. Like it did in the i7 (2)

So I’m just looking for some insight, could it be the ribbon cable? I swapped that also as I replaced it in the i5 (1) in the past.