Hey! how do i find wat power is supplying by my PSU

[lynx17]

hi,

hey how do i find wat power supply i have
i bought my pc 1.5 years ago and since then i am unable to play games without hang,desktop crash and restarting.
i replace my Gf 2 mx-400 with a inno3d Geforce 6600(128mb-128bit) agp
but the problem still there.
i m a low end user my specs are.
Amd Athlon xp 2100+@1.73 Ghz
Msi km4am
512 DDR(400 bus)
40 gb Seagate BARACUDA(7200 Rpm)
inno 3d GF 6600 agp (128 mb-128bit)
local PSU having no name but written "switching power supply model atx 300 watt" which is actually the problem i think so.
so any body there help me, why the system restarts and crashes to desktop while playing 3d high gfx games like COD2 and Q4 and D3 & NFS MW.
system runs fine and with no freeze while i m not playing games or doing anything xcept game.
quick replies appreciated.

 

[N3051M]

if its noname than rule of thumb is that 300(not equal to)300 watts... more like 10-15% lower (i think)
this thread should help you out.. especialy the calculator to find out what you realy need
https://www.techspot.com/vb/topic34724.html
also check if your pc is starting to run a bit hot because high end games like those tend to use a lot of grunt out off everything, and that means heat as a byproduct.. if thats the case you might want to look at having additional fans or some other cooling devices...
N3051M