Power supply issue?

[GoneFishing]

Lately my computer started to reboot periodically ( with new video card installed and when I launch some "heavy" applications , for example :-) games  )
I entered into BIOS and checked Hardware Monitor page . There I saw somewhat uncommon and what I've never seen before - 3.3 voltage value in red color :

3.3V Voltage   [2.816V]

All other voltages are in their usual color.
I think it's a BIOS warning . Is it time to replace a noname power supply with new one ?
   

[dedndave]

the +3.3V supply is derived from the +5V source of the power supply
the +3.3V regulator is on the motherboard
if +5V is good, it may not be the supply

if you have a meter, you can check +5V - it should be at least 4.75V
another thing to try would be to put the old video card back in and check BIOS again

[GoneFishing]

  5V Voltage  [4.632V]
12V Voltage  [12.712V]

[EDIT]: I've seen these voltage values with my old card installed . Computer doesn't reboot by itself though. When I put a new card in and want to play a videogame - I must terminate EXPLORER process to avoid unexpected shutdown ... strange  :icon_confused:
Unfortunately I don't have a meter

...
the +3.3V regulator is on the motherboard
...

I'll look into motherboard manual for jumper settings

Searching on internet gives lots of similar complains . In the most cases the problem is in cheap no-name PSU.

BTW what  3.3 Voltage is designed for on the  motherboard?   

[dedndave]

the CPU uses a lower voltage because it allows for a faster slew rate between logic levels

4.632V is out of spec, should be 5V, +/-5%