What could be limiting my overclock?

[duragezic]

I recently upgraded to a 2400+ mobile (45 watt), shuttle an35n-ultra, and 2x256mb PC3200 buffalo memory. Oh and a alpha-cooling hsf, I forgot the model, but it has the adjustable fan speed in the back and the blue LED. Anyway, right when I got it I switched to 11x200, kept at default voltage. I've ran it like that since and have discovered no problems. But even when I simply tried a 11.5x200, it would take like 10 seconds to restart and load the CMOS screen, and I think it wouldn't boot, I would have to press 'del' and drop it down to 11x200 and it was fine.

My temps at 11x200 are about 40° idle, and 45-50° under load. So not the coolest temps, but I didn't have the money for slk/panaflo what-have-you deal, but definitely acceptable. And I left my cpu voltage at 'auto', although the BIOS reads it has 1.55v, even specififying 1.45v it would read 1.55-1.56v, so I'm assuming it's either reading wrong or setting wrong.

I would like to get a little more out of this cpu without stressing it too much or having high temps, but I'm not sure why I can't even boot 2.25ghz when 2.2ghz has never caused any problems all this time.

 

[Evdawg]

Your ram could be the problem.. having good ram while overclocking is very important. Try fiddling with our ratios. Try 4:3 and overclock from there

 

[charloscarlies]

What PSU are you running?

 

[DaNorthface]

maybe you reached the limit of the cpu at that voltage. raise the vcore voltage and increase the multiplier..

 

[duragezic]

Well Buffalo RAM I heard to be pretty good, but yeah I did back up on the timings, to 'optimal' as opposed to turbo or aggressive that I used at 11x200. But it is only rated for cas3 I think. I'm not too up to speed on RAM timings though, but I hear 2-5-5-10 is best or something??

My PSU is a 300w unit of my Inwin q500a. I checked the rail readings, and none of them were close at all to the maximum the PSU is rated for (the +12v specifically was quite low surprisingly). And I'm only running one hdd, two cd-roms, 1 case fan, and a 9800 pro. But yeah I know how important the PSU is, but I didn't have the money to buy a new case with my upgrade so I'm making do with the Inwin for a another month or two.

I will definitely try a higher voltage but does anyone know if its reading wrong or if its setting it high? If its the later I'm surprised it wouldn't do 11.5x200 if its really at 1.55v!

 

[JeffCY]

I think some motherboards just tend to overvolt and some undervolt. For example I set mine to 1.725 and according to MBM it averages 1.69-1.7.

 

[DaNorthface]

1.55 volts isn't alot at all.. making it to 2.2 ghz with that voltage is pretty good actually, it may not be the best but it's good as or better than average.

 

[jswjimmy]

try uping your vcore, the an35n-400ultra link mine undervolt by as much as 0.05 volts

 

[oconnect]

Originally posted by: JeffCY
I think some motherboards just tend to overvolt and some undervolt. For example I set mine to 1.725 and according to MBM it averages 1.69-1.7.

I have the same problem on my DFI Lan Party NFII Ultra B. I have to set it at 1.725 t get 1.7 volts.

 

[S4M33R]

Your cpu probably needs more voltage. Try looking here for more tips.

 

[duragezic]

Ok well I'm too tired tonight but I'll up it to max of like 1.7v and see if that was the problem. I was hoping maybe closer to a 2.4ghz o/c rather than 2.2ghz with this cpu, but I couldn't go any higher than 1.7v probably or even get to 2.4ghz cause of my cheap hsf, but I might worry about getting a better one somewhere down the road.

 

[ku]

Jack up your voltage man... Despite whatever the program may say, jack the voltage up a tiny bit and see if that helps at all. I'd say you're safe up to about 1.8v (to test, not to leave it there)

 

[duragezic]

Ok being the geek I am of course I wasn't gonna goto sleep without at least messing with it a lil', and I finally got it to run at 11.5x200/2.3ghz, and required all the way to 1.625v from default. With each little bit of voltage I added it finally booted into windows and is working ok now but I suspect an additional .025v will be required for games to be stable. So I doubt I will get much more. Seems like a lot just for 100mhz! I probably won't go higher than 1.75v, but I guess my goal of 2.4ghz would maybe be possible with 1.75v. And what's nice is my cpu temp has not changed at all from the idle temp @ 2.2ghz, which is 39°, er wait it's 38° now!

edit: Make that 12x200/2.4ghz @ 1.75v (or if undervolting, its reading 1.725v) now, but instant error in Prime95 test. Temps only up to 42° idle though, not too bad. I probably can't go any further but could tweak a little bit with the FSB instead of the multiplier or tighten the ram timings.

 

[S4M33R]

did you get a 35 watt or a 45 watt mobile?

 

[duragezic]

Using the 45watt mobile.

 

[JeffCY]

Originally posted by: duragezic
edit: Make that 12x200/2.4ghz @ 1.75v (or if undervolting, its reading 1.725v) now, but instant error in Prime95 test. Temps only up to 42° idle though, not too bad. I probably can't go any further but could tweak a little bit with the FSB instead of the multiplier or tighten the ram timings.

The more important temperature is the load temperature. How high does it go?

 

[magratton]

You need to set the voltage to the CPU to about the following (actual voltage using mbm5 or speedfan to measure, bios setting may vary depending on whether your board over/undervolts):
2300 (200x11.5) 1.6 - 1.65
2400 (200x12) 1.65 - 1.7
2500 (200x12.5) 1.75 - 1.85v

YMMV, but that is what I have found on 3 different mobiles. On my Abit NF7-S v2 I set the bios to 1.675 (1.65v actual) and run 2400 (200x12) happily all day long. Remember, the mobile is meant to run it's speeds with less voltage (good for laptops). But if you put it up to the same voltage as it's desktop counterpart (e.g., Barton 2500 XP which runs at 1.65v) then you can push more through the mobile chip. Don't be scared, set that baby to 1.675v 200FSBx12multi in your bios and you will be running happy in no time.

 

[duragezic]

UPDATE: At 2.4ghz, it was unstable even in windows usage so I dropped it down to 2.3ghz @ 1.675v. IIRC Prime95 got an error after not long at all but my system has been completely stable otherwise. The most intense thing I do is gaming. I was just playing some Joints Ops and I checked MBM and the max temp reached was 49°. It's back to idling at 40-42°. So, decent temps still given the hsf I'd say, but I might just go for a few more mhz with a higher FSB rather than try for a stable 2.4ghz at this point. The box says my hsf is actually only rated for 3400+ (at the highest rpm speed, dropping to med/2200rpm raises temps by 2 or 3) Bartons too, so it's about maxed I'd say.