Underclocked K6-500 at 1.9v on laptop!

[Crashman]

My friend had a K6-2 380 laptop with burned L1 cache. So I told him he needed a new processor, there was a place selling 500's cheap, the 2.2v version.
I installed the processor at 400MHz, and dropped the voltage from 2.2v/3.3v to 1.9v/2.5v. Now the thing runs faster than with the 380 and MUCH cooler, in fact his CPU fan rarely kicks on! His battery life has also been extended by about 20 minutes! And the 500 was only $3 more than the 400!
He's a very happy camper.

<font color=blue>At least half of all problems are caused by an insufficient power supply!</font color=blue>

 

[Crashman]

What, noone interested in this awesome underclock? Dudes, I reduced heat output and power consumption by a huge amount, something very important on a laptop!

<font color=blue>At least half of all problems are caused by an insufficient power supply!</font color=blue>

 

[Quetzacoatl]

Dude, it's an AMD K6...not that much to brag about...unless you plan on selling it to me *grins*

"When there's a will, there's a way."

 

[Crashman]

Well, let me put it to you this way then...at 400MHz, it's probably faster than the VIA C3 1GHz and puts out less heat as well. If you're interested, he got it from Compgeeks.

<font color=blue>At least half of all problems are caused by an insufficient power supply!</font color=blue>

 

[phsstpok]

Always wondered how hot those mobile K6-2s really get.

Haven't opened a laptop since maybe a Pentium 75. How do newer laptops deal with the heat?

A desktop K6-2 380 ran with a multiplier of 4X and a 95 mhz bus. Is it the same on the laptop?

I didn't realize bus speeds and multipliers were adjustable on laptops.

<b>I have so many cookies I now have a FAT problem!</b>

 

[Crashman]

NO, this laptop did not come with a mobil K6-2, but a Desktop K6-2 instead! Because it was cheap! It even had a PASSIVE MATRIX screen! And the replacement CPU was also a dektop unit! The original CPU was being ran at 6x62.5MHz, the new one at 6x66MHz. And it ran hot, even with the underclocked 500, until I reduced the voltage to mobile Pentium MMX settings.

<font color=blue>At least half of all problems are caused by an insufficient power supply!</font color=blue>

 

[sakattack]

So, were those options available in BIOS or not.

And if not how did you manage to do it?

Great job anyway!

 

[phsstpok]

LOL! Every one of my guesses was wrong!

I am amazed that the desktop K6-2 runs in a laptop. I thought they were power hungry and hot. My K6-2 350@400 Mhz was very hot until I added a Socket A heatsink and a 23 CFM fan. How does a laptop cool it? really? I can see where the 1.9 volts helps (my K6-2 is at 2.8 volts) but it still must be putting out plenty of heat.

Hate those dual-scan displays!

<b>I have so many cookies I now have a FAT problem!</b>

 

[Crashman]

All laptops use boards that are made to support multiple processor types. Unfortunately, this board only supported two bus speeds 66MHz and below, and multipliers from 2x to 4.5x. But the company used the 2x=6x multiplier conversion built into the K6-2 series for the 350, 380, and 400 processors. Like I said, it came with a desktop 380 at 62.5x6 from the factory (along with a lot of other money grubbing, er, saving "features"). This particular unit had the dip switches mounted UNDER the CPU (which caused me hours of grief to find, since I pulled the whole thing apart looking for them).

<font color=blue>At least half of all problems are caused by an insufficient power supply!</font color=blue>

 

[Crashman]

I always use Socket A sized heatsinks with 2.8v. When I first fired the laptop up at the standard 2.2v, the fan ran most of the time, like 5 minutes to cool, then 30 seconds of relief, then 5 minutes to cool. Dropping the voltage was soley responsable for cooler operation, the fan hardly ever turns on now.

The heatsink in this thing is a fairly amazing unit, about 4 inches long and 3/4 inch thick in the long area past the CPU. The part directly over the CPU is about 3/8 inch thick. It uses a 40mm fan that I estimate at 5200RPM, so it's quite noisy when the fan turns on (no longer a problem).

<font color=blue>At least half of all problems are caused by an insufficient power supply!</font color=blue>

 

[phsstpok]

You still didn't say how you lowered the voltage. Are there just jumpers or did you have to do a mod?

I'm still amazed that it can handle the heat. I remember a particular Pentium-90 NEC laptop that would burn if you tried to use it on your lap and would overheat flat on a desk. It was rather inconvenient having to prop it up above a surface so that it would have adequate cooling.

As for my desktop K6-2, I only run it at 2.8 volts because sometimes I overclock it beyond my normal overclock.



<b>I have so many cookies I now have a FAT problem!</b>

 

[Crashman]

The board was designed for both K6-2 Desktop (2.2v/3.3v) and Mobile Pentium MMX (1.9v/2.5v) CPU's. Probably designed before the introduction of the mobile K6-2. So I simply cross referenced the DIP switch settings to find the lower M-P-MMX voltage settings and used those. I was more concerned with whether the CPU would be stable with the 2.5v I/O than the 1.9v core settings, but both worked!

<font color=blue>At least half of all problems are caused by an insufficient power supply!</font color=blue>

 

[Crashman]

Oh, I've run lots of K6-2's at 2.8v on desktop boards without "official support" for them because that's the only split voltage many desktop boards supported. In fact, probably 90% of the early Pentium MMX boards would work with the K6-2, using the 2x=6x feature, simply by using the 2.8v setting and a big cooler. So I'm completely familiar with the type of setup you're using. In fact I've sold a lot of systems (with warranty) in that configuration.

<font color=blue>At least half of all problems are caused by an insufficient power supply!</font color=blue>

 

[phsstpok]

The board was designed for both K6-2 Desktop (2.2v/3.3v) and Mobile Pentium MMX (1.9v/2.5v) CPU's. Probably designed before the introduction of the mobile K6-2. So I simply cross referenced the DIP switch settings to find the lower M-P-MMX voltage settings and used those. I was more concerned with whether the CPU would be stable with the 2.5v I/O than the 1.9v core settings, but both worked!

U da man!

Actually I hate opening laptops. (It's kind of like me and cars). I understand a lot but I'm all thumbs. I always miss something in those jigsaw puzzles called laptops. Snap! (Forgot another screw!)

<b>I have so many cookies I now have a FAT problem!</b>

 

[phsstpok]

Oh, I've run lots of K6-2's at 2.8v on desktop boards without "official support" for them because that's the only split voltage many desktop boards supported. In fact, probably 90% of the early Pentium MMX boards would work with the K6-2, using the 2x=6x feature, simply by using the 2.8v setting and a big cooler. So I'm completely familiar with the type of setup you're using. In fact I've sold a lot of systems (with warranty) in that configuration.

Actually, the FIC 503+ that I have supports core voltages as low as 2.0 volts. I just set it to 2.8 volts for overclocking and don't worry about.

I have seen your other posts regarding mobos that don't support the lower voltages. I wanted to try it with my HX mobo but I never thought another K6-2 was worth the expense plus I could never get the HX mobo to work reliably with more than one DIMM. I don't want to buy any SIMMS, either.

<b>I have so many cookies I now have a FAT problem!</b>

 

[Crashman]

I forgot that's what you had. You know it took VIA TWO YEARS to come up with the working drivers and necessary BIOS updates to make that board stable. At least FIC was kind enough to incorporate those BIOS updates in a timely manner. Yes, I bought one of those boards new, because at the time it was the "Latest, fastest board for the AMD CPU". LOL, it didn't work with most of my hardware until after the updates, then it still wouldn't work with PNP for Windows and had to use BIOS PNP instead.

<font color=blue>At least half of all problems are caused by an insufficient power supply!</font color=blue>

 

[lhgpoobaa]

hmmm interesting

my mum has a k6-380 laptop... maybe i can do some creative surgery on it :lol:


Proud owner of the <b>Beige Beast</b> :lol:

 

[phsstpok]

You can imagine how much fun it was (a couple of years ago) trying get an FIC 503+, an overclocked K6-2, a Geforce256, and a 13 year old, 230 watt, AT power supply to work together.

A year later it was relatively stable. It took Via 4.29 drivers and a 300 watt ATX power supply.

One good thing came out of the experience. It taught me how important a "clean install" of the Via 4-in-1 drivers really is. They get easily corrupted, especially when combined with nVidia drivers.

Do a clean install of each of the Via 4-in-1's, nVidia Detonators, and DirectX and a whole lot of problems are eliminated, including Windows booting to a blank screen with a blinking cursor, Detonators stuck in 640x480, 15 colors, 3D games just freezing (usually with looping sound), 3D games just dumping to the desktop, and more that I can't remember off-hand.

<b>I have so many cookies I now have a FAT problem!</b>

 

[Guest]

wow, this was posted 6 years ago (its 2008 now innit??) un i just got given FREE, right here in front of me an old laptop with an AMD 366 cpu in that i wanna play with un try to underclock cos its just way to HOTTT.
crashman... yep u rock dude, this is exactly what i wanted to find out. mine's 2.2v/3.3v i/o. ive already lowered the 2.2v to 2.0v (still ran HOT), then to 1.8v (un still it runs HOT).
was just wondering if i should try lowering the 3.3v i/o to the 2.5v i/o setting (for a mobile cpu) but werent sure if that was too much of a drop un it might blow it up completely or sommit ???
but seeing as uve tried it un it ran COOL, i gotta try it man.
RIGHT NOW in fact ;0)
brb...fingers crossed !