CPU need help undervolting cpu

hello need help undervolting my phenomII x4 955
so far i have managed 1.225 volts this is the stock so my previous try to 1.2 didn't work on my asrock nforce 6 . i dodn't know how to check the stability of my cpu currently i'm runn prime ninty five
the main reason i'm undervolting is because of my 250w power supply which isn't able to support a full fat phenom II cpu, a hd5570, 2 hdds, 2fans (cpu fan is ridiculously loud at 5200 rpm -is that the normal speed of a stock cpu fan) also should i also underclock
current screenshot of prime 95 running
(please right click broken image to view on another tab screenshot sorry but for some reason you can't view it

 

now my cpu fans reached 5850 rpm but i isolated the reason for it
a fan blows cool air into my computer when i take the fan off the cpu fan reduces its speed to normalish level
i'm gonna let the fan run as i cools alot of other components
and keeps my phenom II temperature at 46c

 

First thing is under volting will bring th temps down a bit, but you still need the fan on the CPU. Go into the bios and make sure cool and quite is enabled, that will keep the fans speed down and keep the noise down as well.

 

thanks but i reduced the fan speed using the bios i don't want to enable cool and quiet because it might reduce the stability of my machine( i don't know if that is true please correct me if i am wrong) also i increased the vcore to 1.25 i'm not checking for stability since i don't think in real life i will be i will really tress my cpu as much.

also when i stressed my cpu when it was 1.225 volts it ran stable for around for around 45 mins on p95

do you think i should stress it

 

playing farcry 2 for twenty mins to see if my pc is pullng more watts than i can feed
will play crysis warhead later as it is more taxing

 

Cool and quiet will be fine, all it does is read the temps and increase the fan speeds as necessary. I keep it on even when running big overclocks. I don't think you need me to tell you, but hat PSU at 250watts really is the weakest link in your rig.

 

yeah i know i have fsp atx 500w but only server 2u psu's fit in my case

 

Awww, undervolting a PII X4 is such a waste lol... that CPU just begs to be pushed super hard! Ditch that case if you can't use "real" PSUs in there, it's just crippling you

 

oc junkie how many volts did you use for for you 3.8 ghz clock

 

thinking of getting this

after getting this

it is 460 watts

 

latest

 

3ghz at 1.184 it think it is good

lower than the phenom II x4 910e which is a 65w tdp part

 

1

 

still running prime ninety five with no issues

 

Cool and quiet only affects stability of high overclocks, should be fine the rest of the time.

TBH I expect it's the graphics card that is pulling the most power, even if you undervolt by half a volt, it's not going to take a huge chunk out of your power consumption.

It looks like that PSU was designed for computers that were around a long time ago (judging by the low wattage), before graphics cards needed PCIe connectors. I expect the amount of power each rail can supply will confirm this.

Older computers were more reliant on the 3.3v and 5v rails, so they didn't need very high 12v rails. Nowadays it's the 12v rail that is the important one to look out for. Just out of interest, how many Amps can that PSU's 12v rail supply? should be on the side of the PSU itself.

Does the PSU even have a 24 pin (or 20+4 pin) plug for the motherboard? some of the extra 4 pins carry extra 12v power needed for PCIe slots.

If you have a 500W psu that doesn't fit, if I were you I'd find a way of hooking it up outside the case, even if you couldn't close the case properly for now, you could always find something temporary to cover it with. Saves a lot of time and faffing about and stress testing with voltages, you know if you want to be absolutely sure your PC is stable you'll want to run prime95 for over 24 hours.

And before you spend money on the new PSU, check the rails, it will probably need to have at least 28-30A available via a single or multiple +12v rails (not-12v) if you want to run a 450, 25A absolute minimum.

Edit: an easy way to cut the power a CPU uses is to disable cores in the bios, but as a CPU only uses as much power as it needs at the time, it's not going to help much if the game is single threaded.

 

it has 20a on the 3v 18a on 5v and 15a on 12v it has a 24 pin plug for the motherboard and 4 pin for the cpu
i'm running a hd 5570 so i don't think that it is taking much power it is a low profile single slot card

 

If the card doesn't have an extra PCIe connector it should draw a maximum of 6.25A, some cards like the 8800GT have been known to draw more than the 75W a PCIe slot should provide. 15A does seem pretty low in comparison to today's PSU's.

 

thanks will keep that in mind
currently also paying attention to my case mod so i might not upgrade
for a few days

 

@rayson
It's a C3 doing 3.8 on STOCK volts (1.35) just with the multiplier so I'm sure I can pump it a hell of alot further, just haven't had alot of time to seriously push it. It's going underwater soon too so the goal is to hit 4 gigahops