View Full Version : PSU, negative 12V and 5V rails?

04-22-04, 04:44 AM
Since I upgraded my CPU last night, I installed MBM5 to monitor temp levels for a while to make sure everything is alright.

I don't remember seeing any values for the -12V and -5V rails in the BIOS, but MBM shows some. These values are waaaay off. :retard:

+3.3 : 3.31
+5.0 : 5.00
+12.00 : 12.04
-12.00 : -2.54
-5.00 : -1.20

These are the low values after roughly 600 readings. I put some load on the box.

I read somewhere -12 and -5 cannot be measured anyway so maybe MBM is making this **** up? :screwy: Or should this worry me?
I only keep reading about the positive rails which are well within spec. For now I assume this is no reason to worry. Even more so considering I cannot find any info on negative voltage rail monitoring anywhere. Of course the box is running stable as ever.

This is a 350W Enermax PSU.

Of course, I'm kinda curious about voltage levels recently regarding the upcoming GPU upgrade. :ORDER:

04-22-04, 07:50 AM
Think you right about MBM and the neg rail readings.
As far as your 350W I personally think you will have no problems with 6800 as the 350W psu's from Enermax have a history of being good quality. I cannot be for sure about the 6800 as I do not have one, yet, but with the amps supplied by your psu I see no reason why the 6800 would require any more. Naturally, if you add more power hungry components to your system and overload the capability of the 350W you will have problems.

04-22-04, 08:32 AM
Here is a fun program to calculate the approximate watts used by your system.


Note that the Athlon64 is not yet listed and of course the 6800 series cards. It has been reported that the 6800 takes 110 Watts at peak compared to the 75-80 Watts for the FX series.

04-22-04, 08:58 AM
Here is a fun program to calculate the approximate watts used by your system.


Very cool. Thank you! According to this:

"Your Recommended Minimum Power Supply is 341 Watts!!*"
Current graphic card is calculated at 30W.

When I bought the Enermax long ago, I got it for reliable, adequate power and quiet operation. It was equipped with a special fan. :p

It's a modified Enermax EG351P-V (ATX 2.03) model which unfortunately has not the strongest +12V rail. (rated 12A) :cry:

I will still give it a shot with one of the next gen cards (ATI/nVida) before bothering to upgrade it. I will only consider an upgrade should I notice voltage monitor changes. I will of course closely monitor those rails for a week or so.

I was just looking for an option in MBM to disable the monitoring of both the -12 and -5 voltage rails. This did not seem possible but I found several voltage configurations for my mainboard type (P4T-E). Using "AS99127F Standard 2" instead of "AS99127F Standard 1" obviously fixed the wrong readings. Now:

-12.0: -11.61V
-5.0: -5.24V

Looks good. :thumbsup: