Celeron 600: How do I change default core volt?

[john deere]

I want to increase the default core voltage on my Celeron 600 cB0. CPU default is 1,5 and it doesn´t go higher than 1,7 in the softmenu. I´ve tried changing voltage via the jumpers at the converter card (MSI 6905) but the softmenu seems to override these changes because after I boot, 1,5 is still default core volt.

I have a feeling I´m doing something wrong. Should I clear CMOS via that CMOS jumper after I have changed voltage on the converter card? Is there something else that should be done at mobo/conv.card besides changing the voltage switches?

Motherboard is Abit BH6 v1.1 with the latest BIOS update.

Suggestions?

/John

[mugambo]

A default voltage of 1.5 on a Celeron 600 sounds wrong. Seems like the B0 steppings had default voltages of 1.60 and 1.65 volts. I will check. Anybody know this?

Dave

[batboy]

The default vcore on a cB0 600 Celeron is indeed 1.5v. You could do the VID pin wire wrap trick on the CPU, but there is an easier way since you have a BH6 mobo. Look up to see how you do the BIOS flash trick to gain higher voltage settings. It's been so long since I had a BH6 that my mind is fuzzy. Seems like you set the BIOS settings up as high as you can, then flash the BIOS to the most recent upgrade (it could be the same one you have now if it's the most recent). That is supposed to give you more voltage options. Do a search first to make sure I've told you correctly.

[JaY_III]

Originally posted by mugambo
A default voltage of 1.5 on a Celeron 600 sounds wrong. Seems like the B0 steppings had default voltages of 1.60 and 1.65 volts. I will check. Anybody know this?
Dave

nope, batboy hit the nail strait on the head with that one
see HERE (http://processorfinder.intel.com/scripts/list.asp?ProcFam=49&CorSpd=5044&SysBusSpd=ALL&PkgType=ALL) and check out SL3W8 and SL46U, both cBo steppings, and run at 1.5V....

It was not untill Intel release the 633 (and up) cBo stepping celerons did the defualt voltage change to 1.65V

edit:
to get your voltage higher than 1.7V,
set your voltage to 1.7V and reflash your BIOS.
Your computer will then think 1.7V is you defualt and then alow you to raise your defualt Vcore another 15% higher

[john deere]

Thanks for the replies everybody.

It is an SL46U so it is, like you said, running 1.5 volts as default.

Anyway, I researched the Flash BIOS trick and it seems like a fairly easy for way to change the default voltage. Although there is one thing that makes be think it wouldn´t work: I flashed BIOS right before I put this CPU in my computer. If the flash trick really works, wouldn´t I already have a higher default voltage (which I haven´t) because of the core voltage on the former CPU? Since I flashed BIOS with an Celeron 400 running at 2.0 volts, wouldn´t (according to the flash trick) my default core voltage be 2.0?

Or does removing one CPU and installing another reset everything? That would mean that if I removed my current CPU (the Celeron 600) after doing the flash trick, I would have to do the flash trick again, right?

Please bare with me, I´m a total newbie to these things... :-)

/John

[JaY_III]

Different CPU, different Voltage ID so that is why the defualt is not 2.0V....

And i do think if you remove the 600, and put the 400 back you will have todo the flash trick again

[john deere]

Oh, one more thing:

According to the link Jay posted, there are two versions of the Celeron 600 that has a default core voltage of 1.7 (cC0 stepping, spec. numbers SL4PB and SL4NX) and another two versions of Celeron 600 (cB0 stepping, spec. numbers SL46U and SL3W8) that has a default voltage of 1.5.

Does that mean that it would be safe to go to about 1.9 volts on the cB0 version even if it has a default voltage of 1.5? Are there any differences between these steppings, besides what Intel chose to be the default core voltage?

/John

[john deere]

Ok Jay, thanks.

/John

[JaY_III]

DO NOT use 1.9V
i woulndt go any higher than 1.85...
really 1.7-1.75V is all you should need......
but even then it can be risky....

Without knowing what your temps are like, i would stay away from 1.9V. Your CPU still most likly start to get flacky on you once you hit temps in the mid-upper 40's....

Rember, Cooling 1st, Voltage second.
That way you wont have a dead CPU on your hands

[john deere]

Thanks for the warning and the instant reply Jay.

Well, I would like to give 600@900 a shot and I figured I would need 1.9 v for that. Maybe it works at lower voltages but it hangs in boot at 9x100 at 1.7 volts. 9x95 at the same voltage seems to be the limit at this voltage - it boots fine but can hang after a while.

Right now I´m at 9x90, 1.65 volts and that seems very stable. System temperature is 31-32 C after a two hours of 3D-gaming. Since the BH6 only has one sensor about two inches from the CPU, I don´t know the temp at the CPU. According to Intel´s site the recommended max temp is 45 C, measured 0.3 inches above center of the CPU-fan.

/John

[JaY_III]

You do have PC-100 RAM correct?
if you still have PC-66 RAM, that could be holding you back

If you have a sensore, it should fit under the heatsink, try to place it as close to the CPU core as you can.... that will give you the best temp, the way you have it set up is only giving you your case temp.....

My cBo 633 needed 1.8V for 100FSB
Friends cCo needed 1.75V for 100FSB.....
too bad no 2 chips are the same :rolleyes: would make things so much simplier....

but with the right RAM 100FSB is almost a given with that CPU...
Do you know what Heatsink you have? and are you using thermal Paste (brand?) or the thermal pad (bubble gum like stuff) that came on the heatsink?

[john deere]

Yeah, I have 256 mb PC- 100.
The heatsink is an Golden Orb. After reading these forums, I´ve come to understand that these are far from being the best coolers, but I guess I have to live with that for now...I´m going to buy some Artic Silver tomorrow. Don´t know if it´s any good, but I´ll try it anyway.

Considering the temperature and sensors: How much can the temperature differ from Intel´s measuring point (0.3 inches above center of the fan, roughly about an inch above the CPU) and the on-board sensor that is placed about two inches from the CPU?

I´m going to bed now, will be back tomorrow. Thanks for breaking in a noob. :-)

/John