By skyforbes Linux does have stressapptest which is very good for stressing the memory controller (on the CPU) but it it will miss other types of instability issues. Same is try for y-cruncher VT3 and VST.
You can try to run other y-cruncher stresstests (different versions have different tests available) but all those are incomplete so not sufficient by itself even if they can be useful for fixing specific instability problems (same hols true for memtest86+).
Another problem i noticed is that linux prevents 1.2 GiB of ram from being utilized after booting while windows and memtest86+ only has 0.2 GiB being unavailable.
That is a problem when doing ram stresstesting since it prevents all the ram from being properly stressed.
While memtest86+ does allow for more ram to be tested that prevents you from doing anything else on the computer at the time which is a big downside.
The max i can test after booting linux currently (arch linux, XFCE4) is around 63000 MiB. I Could maybe push a bit higher if i enabled a Swap partition but i don't want to shorten the lifespan of any SSD i currently have.
I have not found any way to reduce the 1.2 GiB reserved by linux itself.