Power PSU 500W sufficient for this config. If roughly, the percent of 100W, 150W videos, 50W the rest, at full load only. If there is not enough power, then either the system will shut down (Body, reboot), or the PSU will burn.
Video could "fix", "warm", because the place burnt. Maybe not, just flux, dust, oil thermopause or regular heat "repainted", and everything is OK.
Overheating of the video is how many degrees? 95-105°C? If less, it is not overheating. Just in case of overheating, the video (and the whole computer) cuts off.
Bagel (FurMark) on a cold run? FPS when the heat was falling? I think that everything will be OK.
And now the most interesting - percent of your choice of server (I suspect that this E5-2689 2.6 Ghz), multi-core, as much as 8m cores, right? According to synthetic tests
, the performance of about 13300 parrots. If you take an old 4 core i7-2600K, then it 8400 parrots. Ie percent 2600K is 37% slower.
But if you take the productivity of one kernel, then:
13300 / 8 = 1600 parrots
8400 / 4 = 2100 parrots
Turns out an old 2600K will be 30% more productive in applications that do not support multi-core calculations.
STALKER does not support multi-core calculations, as well as the video card is not weak, I suspect it is because of percent and you fell the FPS in the game, and with the system all OK.
PS: still at "home" Protsiv auto-overclocking (Turbo Boost), auto increase in frequency, if conditions are suitable. The server XS, is this feature there, and then the games performance may be even lower in practice.