Issues with lag cannot find any answers

[Mp3zer]

Specs:

I5 12600k - Noctua NH-U12S

Msi pro z690-a

4x8 Corsair vengeance 3200 XMP enabled

Evga RTX 3070ti

Corsair rm 850x

So i have this issue with pretty much any game Insurgency sandstorm, Warzone, Apex. Its starts off completely smooth 144+ fps never dips below, frame times perfect no spikes then all the sudden after 1 or 2 games or 15-20 minutes my games start to lag feel heavy and microstuttery. Still when this is happening my fps frame time and temps are perfect nothing out of the ordinary. Have tried absolutely everything changed all the nvidia control panel setting to everything they could be repasted my cpu tried turning off turbo locking my fps with rivatuner everything anyone online could think of. I did a memtest and had a error on test 5 and 8 but still any combination of my ram sticks 2 new ones 2 old ones nothing happens still the same way already tried 2 different psu's same thing happened with my i5-12600k and ryzen 5 3600 same with my 2070 with 2 different types of ram. Could it be my motherboard is fried or my ram is bad? I have a blue screen once every 2 months or so but nothing seems to be messed up. I have absolutely no idea what it could be if you have any ideas id love to hear them. I also did a clean install of windows drivers are up to date mobo bios is current nvidia drivers are current chipset drivers are current absolutely everything is up to date.

[191x7]

Check each RAM module, 1 by 1, to find the faulty one.