weird behavior with cpu voltage - X2 3800+ *update*

[MrDudeMan]

not sure if this should go in motherboards or CPUs, so i picked here...


when i put the cpu voltage setting on auto in the bios, the processor is getting 1.43-1.44 volts. i turned the frequency up to 230, or 2300mHz, and the voltage stayed roughly the same. it varied a little high, but not more than .025ish. it seems like it is scaling automatically when i overclock it...

when i am running 2 instances of prime95, the voltage drops to 1.39 or 1.40 and does not come back up. i dont know why...

any thoughts?

edit: oh, and 50-51C is the temp at 100% load%. that should be ok, right? i realize its a tad high but nothing to really worry about fixing hopefully



update

ok i put another x2 3800+ in the same motherboard, EPoX 9NPA+Ultra, and it is still dropping the voltage by upwards of .04-.05 volts.

ive now used 2 different x2 3800+, 2 different 9NPA+Ultras, and 3 power supplies. every single on exhibited the exact same behavior.


This must be a problem with the motherboard!

 

[FullRoast]

That seems like a lot of drop. What power supply are you using?

 

[MrDudeMan]

Originally posted by: FullRoast
That seems like a lot of drop. What power supply are you using?

neo HE 550

how much voltage is too much? it turned itself up to 1.55 when i put it at 260x10. is 1.55 too high? its at 37C idle at this voltage.

 

[Armageddon415]

bump for the same problem Im having with my epox 9npa ultra

 

[jiffylube1024]

Sounds like you both have Epox motherboards, which could be the common thread. Could be an Epox problem (voltage droop is either Mobo, PSU or Mobo + PSU issue).

No problems here with voltage fluctuations on my DFI Ultra-D with a 485W Enermax Noisetaker.


Regarding safe voltage on your X2, it depends what kind of cooling you are using. I'd try to keep below 1.55V on stock cooling (below 1.5V ideally); under 1.57V or so with a good air cooler such as the XP-90 or above.

 

[MrDudeMan]

Originally posted by: jiffylube1024
Sounds like you both have Epox motherboards, which could be the common thread. Could be an Epox problem (voltage droop is either Mobo, PSU or Mobo + PSU issue).

No problems here with voltage fluctuations on my DFI Ultra-D with a 485W Enermax Noisetaker.


Regarding safe voltage on your X2, it depends what kind of cooling you are using. I'd try to keep below 1.55V on stock cooling (below 1.5V ideally); under 1.57V or so with a good air cooler such as the XP-90 or above.

ive got a scythe ninja, so it should be ok i guess. the temps arent that great, or they arent as good as i thought they would be, but i guess 50-55C is ok.

i put it back to 240 and the voltage is between 1.44 and 1.45, but when i load them it drops to 1.397-1.406 range. the system appears to be very stable regardless of this voltage drop.

i have been playing doom 3 @ 1680x1050x32 4xAA 8xAF for 3+ hours with no crashing or anything. i also let prime95 run overnight last night and i woke up with no errors.

it did the same thing with a different PSU (s12-500) so i have a feeling it is a motherborad issue. i actually have (2) EPoX 9NPA+Ultras and (2) X2 3800+'s...but only one is setup. the other will be up and running this weekend, so i will be able to report back then with what i find out regarding this voltage fluctuation and if it indeed happens on yet another 9NPA+.

 

[GuitarDaddy]

Originally posted by: jiffylube1024
Sounds like you both have Epox motherboards, which could be the common thread. Could be an Epox problem (voltage droop is either Mobo, PSU or Mobo + PSU issue).

No problems here with voltage fluctuations on my DFI Ultra-D with a 485W Enermax Noisetaker.

I have the Epox EP-9NPA ultra and the 485W Enermax Noisetaker and I don't have a problem with voltage drop. It overvolts a little, but no drop under full load. The Enermax is a very good single rail PS with a lot of amps on the 12v rail (best for overclocking IMO)

 

[FullRoast]

Just another positive comment for the Epox 9NPA Ultra. I have one with a PC Power & Cooling Turbo Cool 425W running an Operton 170 at 2.46 GHz. No drop at full load, two instances of Prime 95.

 

[MrDudeMan]

weird...i wonder why mine is doing it. ive got 2 really good PSUs that both do it. must be the motherboard...maybe i got a dud

 

[FullRoast]

Bigsm00th - Hold on...


I DO see similar behavior. My latest run of Prime95 had a fail on core1 after 19 hours. Vcore is set to 1.52 (bios reading) and under a load, was showing 1.50-1.52 on the Epox status app. After core1 stopped, Vcore was showing 1.55-1.56. I will have to look at this some more, but there is a bigger range of voltage swing than I had seen before. In my case, I did not see the Vcore droop under a load, but I did see more variation.

Update - In my case, I set the Vcore in BIOS, say 1.42. I check the PC Health in BIOS and it shows 1.42. I boot Win XP, start the Epox app., and it shows Vcore higher, maybe 1.50. Then I start running Prime95 and the Epox app shows 1.42. I don't know if the actual voltage droops or the Epox app is not accurate, or something else. I'll keep looking when I get a chance. This was also a quick look, so I may not have the details exactly right.

 

[MrDudeMan]

Originally posted by: FullRoast
Bigsm00th - Hold on...


I DO see similar behavior. My latest run of Prime95 had a fail on core1 after 19 hours. Vcore is set to 1.52 (bios reading) and under a load, was showing 1.50-1.52 on the Epox status app. After core1 stopped, Vcore was showing 1.55-1.56. I will have to look at this some more, but there is a bigger range of voltage swing than I had seen before. In my case, I did not see the Vcore droop under a load, but I did see more variation.

Update - In my case, I set the Vcore in BIOS, say 1.42. I check the PC Health in BIOS and it shows 1.42. I boot Win XP, start the Epox app., and it shows Vcore higher, maybe 1.50. Then I start running Prime95 and the Epox app shows 1.42. I don't know if the actual voltage droops or the Epox app is not accurate, or something else. I'll keep looking when I get a chance. This was also a quick look, so I may not have the details exactly right.

that is exactly what mine is doing. either the motherboard has trouble keeping a steady voltage or the app is just wrong. i find it hard to believe software would misread like that though...which doesnt sound good.

 

[MrDudeMan]

updated

 

[Zebo]

Don't launch everest you'll faint at PSU rails.. EPOX is noted for poor voltage monitoring.

 

Originally posted by: Zebo
Don't launch everest you'll faint at PSU rails.. EPOX is noted for poor voltage monitoring.

ok so they might not actually be that bad? the computers are both running fine...prime95 for hours and hours without a problem, but that voltage seems bad.

edit: this is my girlfriends account, just FYI. i forgot i was logged in as her.

 

[Andres3605]

Is this just the Vcore or is fluctuating in all the rails?

 

[MrDudeMan]

its just the Vcore so far as i can tell

 

[WhoKnowsWho]

Any solution ever come of this? I have been running my board for a little over 7 months now like this.