Thinkpad imc is trolling me

So I have bought a cheap refurbished ThinkPad, with just a basic small ssd and 4gb of RAM, which obviously had to be expanded. The intent was to have a mobile workstation that could replace my desktop when I’m not at home. So I transferred my bigger ssd and bought two 8gb Kingston sticks that were recommended by their compatibility list for the T430. But soon it started crashing. The system always hangs up, green and purple artifacts cover the screen, audio keeps looping and after a while it automaticly reboots. When I have replaced one of the sticks with the original 4gig it happened only once since, but still. Usually it crashed under heavier gpu load when the system got hot, but always just under linux. I don’t use windows normally, but tried running some stress tests on it, however it never crashed. Windows power management is probably more conservative, I don’t know, it seemed more stable. I believe that the memory controller might be slightly worn out and when the leakage increases due to the heat it might not handle a memory intensive load from the igpu. Memtest passes every time and I don’t believe that I have damaged anything when replacing the RAM, or that either of the new modules are bad.
The problem is, that if I want to get it replaced/repaired or anything under warranty, there is no service technician in the world who is going to try to reproduce this issue, it’s unpredictable, only occurred under linux and it wasn’t happening with the original hardware config. Probably my only chance is buying a replacement CPU, but I can’t be sure that it will fix it and I would like to not have to do that.