PIII-S 1.26 @ 1.225 Vcore. Anyone else?

[oldfart]

I know the crowd here is more interested in max overclock, but here is something different. I see posts over @ Anandtech where people are looking to build low power, quiet, or silent systems. I've been playing around with my PIII-S 1.26 system.

I normally run the system 152 FSB, 1.44 GHz. Above 152, my nic stops working and 38 MHz PCI is as high as I like to go. Even @ 1.44 GHz, I run with a slight Undervolt of 1.425 Vcore.

I wanted to see how much Vcore is needed @ stock speed. I've been running Prime95 for the last 1 Hr 1.26 GHz stock speed and an undervolt of 1.225 Vcore! Full load CPU temp is 27 - 28 C. I have the stock HS/Fan installed, but I would say it would be possible to run just a Large HS with just a Power Supply fan to remove the case heat.

You guys with Tualerons....can you post what Vcore is needed @ stock speed? I'd like to see how low you can go. Please use Prime95 if possible to verify stability.

[ol' man]

Here is a prelim.

[oldfart]

1.17 Vcore. Nice!

ol' man, you think a setup like that or the one I tried would run fanless?

[ol' man]

Originally posted by oldfart
1.17 Vcore. Nice!

ol' man, you think a setup like that or the one I tried would run fanless?

Easily. I ran my older cel-t 1.2GHz @1.3v for 6 hours without a fan on it. I know yours at its speed would do it. I am going to remove my HS now and see what it can do!

I have been running prime and sandra now for an hour without a hicup.

Uhh just removed the HS fan. Only fan running in this whole system is the PSU fan. You could hear a pin drop!
1.22GHz and quiet. Nice. got a seagate cuda running too which is very silent.

[ol' man]

I would say you will want some airflow like from the PSU going ove the HS. I have cooled a cpu before like I said by convection only but ambient was aroiund 22deg. C. My apartment is around 25~27 deg. C right now and its cooling efforts by convection are not as good:D Had to up the juice abit. i found this out on my other 1.2GHz too. I could not go below 1.25 v though or it would not boot. This chip boots at 1.15v but not stable. I think to cool passively it will need 1.2~1.3v on average. When temp rises so does the need for higher vcore at times which can conflict with keeping the temp down. That extra cache might give you problems but maybe not either.

[ol' man]

Check out these temps! Well we know at these speeds the thermal threshold is very high. With some airflow over the HS it will be fine like from the psu.

[6502kid]

I've been telling people for a while these chips are unusually
cool, in several different respects.....

Last fall, my Dragon Orb3 fried the cpu fan power connector
on my TISU board. I found out at least an hour or 3 later
when I got done playing UT and checked the hardware
monitor and found fan rpm's at 0. Temp only hit 44c or something.
It was at default voltage, and about a 143-145fsb I think.
I did have a 2coolpc blower in there, which helped I am sure.

I had the 1.1a running windows for a little while last night
at 1.425v and 120fsb with no problems.

:p

[oldfart]

Dell and Gateway use that PS duct type of cooling. With a low Vcore, I'd think you could get away with it.

[Rooski]

You guys with Tualerons....can you post what Vcore is needed @ stock speed? I'd like to see how low you can go. Please use Prime95 if possible to verify stability.

Ok, right now my 1.0a is running with stock speed at 1.2v. I tried lower, but for some reason, my st6 will increase the voltage if I select lower than 1.2v.

Been running prime95 for the last hour with no errors, along with looping 3dmark2001 a few times, as well as looping the Serious Sam 1 demos for awile. No problems. Hardware Doctor reports under load cpu temp at 35c (with stock fan at 5v). System temp also shows 35c (closed case).

For about 1/2 hour of testing, I turned off the cpu fan and just used HS (closed case). Under load, cpu temp hovered around 57c and system temp at 45c. No stability problems. I do not use any extra case fans. Just a single PSU fan, and the dinky fan on the vid card.

I know I should test for a longer duration, but this should give some idea. So far, I'm impressed!

Can someone out there try this on their AMD rig? I'm curious to see what would happen :)

[Ausone]

I'm now thinking about buying Celeron 1.0a or 1.1a or 1.2. It seems both can run at a really low voltage, which is so good for I'm planning to run any of them without CPU fan or with a nearly silent one.

I noticed all of you normally run your chip overclocked. I wonder at what voltage your overclocked chip is running. Actually, as an enxtension to this testing, I'm wondering if any of you are willing to find out if your chip could be overclocked even with undervolting.

[oldfart]

Originally posted by Ausone
I noticed all of you normally run your chip overclocked. I wonder at what voltage your overclocked chip is running. Actually, as an enxtension to this testing, I'm wondering if any of you are willing to find out if your chip could be overclocked even with undervolting.
I run my PIII-S 1.26 @ 1.44 GHz. Overclocked, I still run it slightly undervolted @ 1.425 Vcore (1.45 is stock)

[Ausone]

I run my PIII-S 1.26 @ 1.44 GHz. Overclocked, I still run it slightly undervolted @ 1.425 Vcore (1.45 is stock) That's quite impressive. I realize PIII-S is the best choice for me. In order to run a Celeratin, even 1.0a, at, say, 133 FSB for better mem bandwith, you'll often have to raise voltage from default. Even if not, you won't be able to run it undervolted.

I wish PIII-s were priced lower.