3.3V Graph Showing As Red In BIOS - What issues would it cause?

Associate
Joined
7 May 2024
Posts
2
Location
Leicester
Greetings

Yesterday without warning my PC rebooted itself, no message to say it's shutting down, just black screen and then boot up screen.

Windows started to load but then the screen went black again and the boot screen came back on again.

This cycle repeated 3 or 4 minutes until I switched it off.

First thing I did was take the side off and see if anything felt hot but everything including the CPU heat sink and fan felt cool even though the PC had been on for 3 or 4 hours.

I waited 20 minutes and switched it back on... all is fine again.

To troubleshoot I then opened 6 Fire Fox tabs, each with a YouTube video on them, then opened Media Player Classic and loaded a song, then opened the normal Media Player and played a video. After about 2 minutes the same thing happened, black screen, rebooted itself and stuck in a loop.

After 20 minutes it was fine again, I looked in the BIOS and noticed there are a set of 4 graphs, 3 of them are blue/black and one is red/black.

CPU = 1.352V - graph is a quarter full.
5V = 4.575V - graph is a quarter full.
12V = 11.540V - graph is 3 quarters full.
3.3V = 2.90V - Graph is 100% full and red.

I'm guessing I need a new PSU but was just wondering what issues it would cause?
Would this have damaged the motherboard? and/or the CPU?
 
Man of Honour
Joined
12 Jul 2005
Posts
20,570
Location
Aberlour, NE Scotland
That psu needs replacing with something decent not bargain basement garbage. You could end up with corrupted data, instability which you already have and even fried components. Both the 5v and 3.3v rails are out of spec and the 12v is only just within the minimum limit allowed. The allowed tolerances are:-

Supply (V)ToleranceRange, min. to max. (V)Ripple, p. to p., max. (mV)
+5±5% (±0.25 V)+4.75 V to +5.2550
−5±10% (±0.50 V)−4.50 V to −5.5050
+12±5% (±0.60 V)+11.40 V to +12.60120
−12±10% (±1.20 V)−10.80 V to −13.20120
+3.3±5% (±0.165 V)+3.135 V to +3.46550
+5 standby±5% (±0.25 V)+4.75 V to +5.2550
 
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