Playing games while mining crashes GPU

Hello, Sometimes i want to play some not so demanding games after work, but i don't want to stop mining while playing.

I have setup undervolting and Power limit so that the temps are fine during mining and gpu is stable.

but when i try to play (even low demanding games) my pc freezes, or screen goes black, then i receive driver failure or d3d device not found etc.

What causes screen freeze and gpu restarting (driver failure) while gaming and mining? should i increase mV or power limit?

I have RTX 3070 ti Zotac x2 and my mining settings are 825mV and 65% PL and i get stable ~90C on vram on both PCs

In more demanding games i'm disabling mining.

On my First PC i have to use 925mV instead of 825mV because gpu cclock boosts to 1995MHz which causes insta crashes on 825mV

On my second PC on the other hand there is no problem while playing at 825mV in same games that causes crashes on my first PC.

Why is that? is this because of better CPU and more RAM ?

Additionally my GPU on my Second PC never goes above 1860MHz