CPU loading on the PS 5 Volt line

[SleepyKat]

I'm O/C at 1.35 GHz, Vc or 1.70, Temp at 46C full load. My PS is a 300 W. 5 V Line at 4.73 V Stable sofar......
I notice that when I O/C to 1.5 , it is iffy and dies at Win startup. I think that my 5 Volt is dropping too low and is locking up the system. Just had to Reload Win98 cause it got trashed. What is a "comfortable" limit for the different voltages?

[Hoot]

Do you own or have access to a digital multimeter? It would be interesting to see if you are developing too much voltage drop across the wires running from your PSU to the motherboard. When you see that low voltage on your monitor software, measure the +5V on one of your unused plugs and see how much difference there is. Of course, you could have a poor PSU also.

Hoot

[Yomama]

SleepyKat (May 23, 2001 09:56 p.m.):
I'm O/C at 1.35 GHz, Vc or 1.70, Temp at 46C full load. My PS is a 300 W. 5 V Line at 4.73 V Stable sofar......
I notice that when I O/C to 1.5 , it is iffy and dies at Win startup. I think that my 5 Volt is dropping too low and is locking up the system. Just had to Reload Win98 cause it got trashed. What is a "comfortable" limit for the different voltages?

I had the same issue with an enermax 431 ps. It ran at 4.85V at 1.4GHz and got just a tad instable. My PCP&C PS allows me to adjust output voltage which I did -to 5.3 so that it drops to about 5.1 under load.

Yo

[SleepyKat]

Hoot (May 23, 2001 10:01 p.m.):
Do you own or have access to a digital multimeter? It would be interesting to see if you are developing too much voltage drop across the wires running from your PSU to the motherboard. When you see that low voltage on your monitor software, measure the +5V on one of your unused plugs and see how much difference there is. Of course, you could have a poor PSU also.

Hoot
hmmmmm multimeter...should have thought of that instead of relying on the MB. It read 4.94 V for the 5 Volt line...but then again,my Beckman meter could be off....hmm the 12 V line show 12.13 on the MB and 12.44 on the meter... now I don't know which one to believe...

[SleepyKat]

Hoot (May 23, 2001 10:01 p.m.):
Do you own or have access to a digital multimeter? It would be interesting to see if you are developing too much voltage drop across the wires running from your PSU to the motherboard. When you see that low voltage on your monitor software, measure the +5V on one of your unused plugs and see how much difference there is. Of course, you could have a poor PSU also.

Hoot
hmmmmm multimeter...should have thought of that instead of relying on the MB. It read 4.94 V for the 5 Volt line...but then again,my Beckman meter could be off....hmm the 12 V line show 12.13 on the MB and 12.44 on the meter... now I don't know which one to believe...

[Hoot]

A Beckman is just fine. The wire from the PSU add a certain amount of resistance to the voltage path as well as the contact area of the ATX plug. Though small in value, they add up. Paralleling unused conductors from other PSU leads just before the ATX connector helps a little, but do not help with the losses through the connector. There are also small resistances in the motherboard voltage path traces themselves. All these little bits of resistance add up and express themselves as you use more current to achieve an overclock result you are pursuing. The one to be concerned about is the +5. More than any other voltage, it has the hardest job to do. I took an unused +5V lead from one of the PSU cables that had some obscure connector on it, cut one of the +5V leads and soldered it directly to the collector of one of the vcore switching mosfets. It really helps reduced voltage sag under load. I could have done one or two more of those unused +5V wires, but the one reduced the sag so well, I didn't want to complicate the wiring in of the motherboard any further. If you have to remove the motherboard, for whatever reason, now you not only have to unplug the ATX connector, but you have to unsolder wires as well. Luckily, I haven't had to remove my motherboard recently. Like I said in a different post, you could just have a poor PSU. Certainly, not all PSUs of the same wattage, behave the same.

Hoot

[SleepyKat]

Thanks for the info. I presently have an adversion to snipping the wires and solder things together on a new computer. Thanks again