Re: segfault running GL apps on 100.14.09
Perhaps the kernel is eating memory and top is only showing userspace resources (I don't know).
Or perhaps it is overheating. Do the same thing with nvidia-settings displaying gpu temp. Or it could be cpu overheating. If it is faulty ram then memtest could detect it - it is often an option to run on live CDs.
Which games are this? Try another based on a different engine.