Limit on Voltage Drop

[Texun]

Can someone tell me what the acceptable voltage drop limit is for a PS? I seem to remember reading somewhere a long time ago that a drop should not exceed 5% of the rated voltage, but it's been a while and I don't remember if that was a generic rule or a standard.

I'm getting random lockups with nothing showing up in the event viewer.

Here's what I have:
3 year old OCZ ModStream 450, X2-5600, 4DIMMs, 3 hard drives, SB X-Fi, 7600GT, 3 fans.

3.3v is 3.33v
5v is 4.76v
12v is 11.46v

 

[jonnyGURU]

Originally posted by: Texun
Can someone tell me what the acceptable voltage drop limit is for a PS? I seem to remember reading somewhere a long time ago that a drop should not exceed 5% of the rated voltage, but it's been a while and I don't remember if that was a generic rule or a standard.

I'm getting random lockups with nothing showing up in the event viewer.

Here's what I have:
3 year old OCZ ModStream 450, X2-5600, 4DIMMs, 3 hard drives, SB X-Fi, 7600GT, 3 fans.

3.3v is 3.33v
5v is 4.76v
12v is 11.46v

5% is the general rule of thumb. And if software is saying 11.46V on the +12V, then that could cause a problem. Of course, software/BIOS is totally inaccurate so if the PSU is suspect get a DMM and check it.

 

[Texun]

Originally posted by: jonnyGURU

Originally posted by: Texun
Can someone tell me what the acceptable voltage drop limit is for a PS? I seem to remember reading somewhere a long time ago that a drop should not exceed 5% of the rated voltage, but it's been a while and I don't remember if that was a generic rule or a standard.

I'm getting random lockups with nothing showing up in the event viewer.

Here's what I have:
3 year old OCZ ModStream 450, X2-5600, 4DIMMs, 3 hard drives, SB X-Fi, 7600GT, 3 fans.

3.3v is 3.33v
5v is 4.76v
12v is 11.46v

5% is the general rule of thumb. And if software is saying 11.46V on the +12V, then that could cause a problem. Of course, software/BIOS is totally inaccurate so if the PSU is suspect get a DMM and check it.

Can a reliable test be done one a spare molex? Getting to the board's power socket was a little dicey so I went with the spare molex connector and have a solid 12.05 and 5.0v with Speedfan showing the above. Now if I start Prime95 in the torture test the 12v will drop to 11.9 on the multimeter and 11.33 in Speedfan.

 

[jonnyGURU]

Originally posted by: Texun

Can a reliable test be done one a spare molex? Getting to the board's power socket was a little dicey so I went with the spare molex connector and have a solid 12.05 and 5.0v with Speedfan showing the above. Now if I start Prime95 in the torture test the 12v will drop to 11.9 on the multimeter and 11.33 in Speedfan.

Although a "spare Molex" doesn't reflect a voltage drop caused by resistance from a load, it does show that the software is probably off (either that or your DMM!) with that big of a difference. Remember, software is only reading one lead, from one place on the board, after it makes it's way through the board and to a chip that uses an algorithm to calculate voltage.

Your .15 drop isn't unusual, and it's still within spec. That said, do double check the 24-pin connection to the motherboard. Those are the wires the BIOS is getting it's voltages from. If it's a good fit, start troubleshooting your lock ups elsewhere.