"Hissing" mobo with new AW 240W psu. (G73)

I recently upgraded my graphics card to a 6990m and as mt cpu alone was set to 93W I thought that i would need at least a 200W psu to poaer my system. It ran well with even the 150W power supply and only shutdown when I ran 2 benches at the same time. It still will shutdown when doing the same thing but not as easily.

Anyway. after I replaced the PSU I started getting these faint hissing sounds coming from my mobo. I did get them before but not this loud. I only get the sound when the PSU is plugged in. On battery power it is silent. Under load the hissing isn't as loud or maybe it is more high pitch and thus less hearable.

I was wondering if there was a known fix for this issue.

 

You sure its the motherboard and not the card? My Caps on my 5870M use to make a hissing noise when under load.

Check the brick is the correct voltage. The motherboard should be ok drawing the power needed.

 

I cant be sure but it sounds more like the mobo especially since when i load the cpu the hissing subsides. I also just took the backplate off and listened and it sounds like it is not coming from the graphics card. the brick is specified on the bottom to be 19.5V, the correct voltage.

EDIT: it is more of a hissing mixed with a buzz.

 

Check how much power it is drawing and under load if it is stable and does not zap and see if there is throttling.

Just don't leave it on when you are not there

 

Sounds ominous... Can you confirm the outlet you're using is properly grounded? Have you tried other outlets? ...in another building?

I agree with @Yiddo - don't leave it plugged in when you're not using it until you confirm what's happening...

 

"does not zap" if you mean hiss/buzz I can confirm that under load there is not hissing. I had the same idea not leaving it on while I'm not at my laptop.

This house is over 50 years old so i could be the supply cables or grounding. I can try again at a mates place this afternoon. I will also test the ground at this point and try others.

just so you know its not super load or anything. If it is quiet and the fans are low I can just hear it. sitting in my chair, otherwise I have to lay my head on the keyboard.

Edit: I don't have the equipment to check the power draw right now. I can confirm that the cpu uses around 85W in the throttlestop bench and I'm assuming in kombustor my graphics card is drawing at least 100W.

Edit2: Bad news... I am getting the sound even when on battery power now... its more of a buzz than a hiss now. I guess i will have to live with it until either my mobo dies or it fixes itself. I just hope its not my graphics card.

Edit3: Ok, from prior experience a buzzing mobo is just a loose inductor. If this is the case I may be able to find it. I have to dismantle to do a cooling mod anyway so I will check then and report back here.

 

If you use ThrottleStop and play around with the C States, sometimes this can significantly reduce the hissing / whine noise that some motherboards make. This can get very irritating.