It might be possible, but it's very complicated. You need to find a board with a modded bios that supports the K6-2/3+, and witch can provide the needed 2.2V for the CPU (most socket 7 boards only go as low as 2.8v). Then you need to disable extrenal (motherboard cache) from bios.

K6-2/3+ CPU's are best used in super socket 7 platforms. They're wasted on a regular socket 7 board. Besides, my P 233MMx build does just fine with 64MB of ram (win98se), I don't see why you would want more...

its not true, it just reduces the performance loss.
the k6-3/2+'s l2 cache does have an almost unlimited 4gb cacheable range, but it would only contain 128kb or 256kb or data. and when you need to access larger data than that, you would have to access onboard cache or uncached dram.
the performance loss depends on chipset. for example, ali5 has very fast sdram performance which is almost as fast as onboard cache, so disabling onboard has very little impact on performance.

I confirm that on a Socket 7 Pentium machine disabling L2 cache has almost no performance loss (10% max) due to the RAM being practically just as fast.
But with faster CPUs like Pentium III the L2 cache has much more significant impact.
The later cache levels are slower than the ones that closer to the CPU.

Well there you go. I say if you want more ram go for a super 7. These can cache from 128mb to 512MB of ram depending on motherboard and CPU combo.

On the MVP3 there's no performance loss with 256MB of ram when using a K6-3+ with L3 (motherboard) cache disabled. For 512MB you need to have L3 cache enabled, but you will see a small performance loss (mem read goes from 280-290mb /sec to ~240mb/sec) The Ali V chipset can normally cache 128MB only (first revisions) but you can get around that by using a CPU with on die L2 cache. 256MB is doable on the ALi V with a K6-III cpu. For more then that you need the rare late revision ALi 5 chipset witch can cache up to a theoretical 4GB (practically 768mb) depending on the amount of on-motherboard cache.

computergeek92 wrote:

I heard AMD K6+ cpus can fix the Pentium Socket 7 64MB memory cache limitation. Is this really true? If so, what models work with a 66mhz fsb? Is a Bios upgrade necessary too?

I currently have a socket 7 setup based on the Intel 430TX chipset. This system uses an AMD K6-III+ CPU at 500 MHz (6x83). The BIOS was modified to allow use of the K6-II/III+ CPUs. I am using 256 MB of RAM which is fully cached by the K6-III's onboard L2 cache. There are often undocumented jumper settings which allow you to set the voltage to 2.0, 2.1, 2.2, 2.3, or 2.4 V. However, the onboard regulator may or may not be able to handle the current going to the CPU. In my case, I found that the heatsink on the linear regular circuit was getting abnormally hot, but it cooled down after I put a small fan next to the heatsink.

The 430TX supports SDRAM as well as EDO and FRM. The SDRAM works fine with a 66 MHz FSB (K6-III @ 400 MHz) and at full capacity (256 MB). The issue is if you want to run the system stable at 75 MHz or 83 MHz AND at the full 256 MB allowed. I found that if you want to stick with SDRAM, then you need to reduce your SDRAM to a single stick of 128 MB at 75 MHz or 83 MHz. But if I went to 256 MB of EDO RAM, I could run 256 MB at 83 MHz without a problem.

At 66 MHz, you might gain a marginal performance increase if you leave the motherboard's L2 cache enabled. I found it neglegible. At 83 MHz, I needed to disable the motherboard's L2 cache for the system to be stable and I am pretty fussy about the system running stable. If, for example, Windows XP fails to boot in even 1 and a dozen times, I consider the system unstable. Installing XP and letting the system update for several days is a decent start for stability testing.

Personally, I quite like the idea of running an AMD K6-III on these older 430TX boards; I find it kind of exciting to take motherboards to their limits. First look for a BIOS update for your board online. If you fail, you might look here http://web.inter.nl.net/hcc/J.Steunebrink/k6plus.htm or send him an e-mail.

If you ever succeed in this endevour, you will probably then look for the best PCI graphics card for this system. I found that a GF4 will squeeze out the most frames per second. Reference, Re: Best PCI VGA for a K6-III+

On the other hand, I also have an mvp3-based super socket 7 with 2 MB of L2 cache. With that quantity of cache, you can cache up to 512 MB of RAM. A lowly Cyrix MII-433 resides in that system with a Voodoo3 3000. In this light, I am taking Cyrix to the limit, not the motherboard!

I was looking at using one in a Packard Bell, 430VX chipset or i'll try some other similar computer.

The more definitive route may be to use an interposer upgrade, like this one from Powerleap Socket 7 PowerLeap PL-K6-III (ultimate upgrade)

feipoa wrote:

The more definitive route may be to use an interposer upgrade, like this one from Powerleap Socket 7 PowerLeap PL-K6-III (ultimate upgrade)

Looks good, I bet they're rare as hens teeth to find online. I checked.

As for the part itself, the only flaw I see is the lack of heatsink clips. You're supposed to use permanent thermal grease?

Go for the normal k6-3 (without the +), it is also a 256kb cache cpu and much easier to run on the normal socket 7 boards..
You don't need a bios update, just the low voltage (2,4v). Setting the multiplier at 2x will let the cpu run at 6x so with a 66mhz fsb it will reach 400mhz.

The only problem that is left is how big of memory sticks does your board accept. Cacheable area will not be a problem anymore with a k6-3, and it will still be faster than any Intel mmx.

computergeek92 wrote:

I was looking at using one in a Packard Bell, 430VX chipset or i'll try some other similar computer.

You might also want to consider just getting another board for use with more than 64MB (or just put up with the performance loss).
430VX is pretty old for the K6+'s and finding a modded BIOS for such an older OEM board might prove quite a task. A main thing is CPU voltage, most VX boards wouldn't get lower then, say, 2.6v or so I think? And many early split-voltage boards of the time used lineair voltage regulators, so the lower the CPU voltage would be, the more heat it would output, stressing the old board quite a bit (might want to rig some additional cooling so it doesn't overheat).

meljor wrote:

Go for the normal k6-3 (without the +), it is also a 256kb cache cpu and much easier to run on the normal socket 7 boards..
You don't need a bios update, just the low voltage (2,4v). Setting the multiplier at 2x will let the cpu run at 6x so with a 66mhz fsb it will reach 400mhz.

The only problem that is left is how big of memory sticks does your board accept. Cacheable area will not be a problem anymore with a k6-3, and it will still be faster than any Intel mmx.

My 430tx board still needed a BIOS update for a non-plus K6-III.

feipoa wrote:

meljor wrote:

Go for the normal k6-3 (without the +), it is also a 256kb cache cpu and much easier to run on the normal socket 7 boards..
You don't need a bios update, just the low voltage (2,4v). Setting the multiplier at 2x will let the cpu run at 6x so with a 66mhz fsb it will reach 400mhz.

The only problem that is left is how big of memory sticks does your board accept. Cacheable area will not be a problem anymore with a k6-3, and it will still be faster than any Intel mmx.

My 430tx board still needed a BIOS update for a non-plus K6-III.

I stand corrected. I thought k6-2 support was all it needs but even the k6-2 is much newer compared to the 430vx/430tx. So yes, a bios update IS needed for these boards.

I kind of get what you're trying to to do OP - max out that motherboard - but in reality it's already maxed out with 64MB of ram. What you're trying to do is mod it - and in my experience things like this are often more trouble then they're worth... my advice is find a super socket 7 motherboard - AT super 7 boards can be had for 10-50$ depending on source and luck. It will save you a lot of trouble, and you'll get a nice stable machine that can scale in performance from a 386 to a pentium II (using a K6-2+ or K6-III CPU).

I don't like Super7 motherboards, they tend to have buggy chipsets. But yes, I am trying to max out my PB. Though staying with a 166 will be just fine, considering it is a low end system. It did not even recognise my known working PCI Cirrus Logic 2MB non-3D video card. Who knows if it will work with a newer card like an SIS 6326 or ATI Rage XL. Packard Bells are weird, ya know.

I find working through all the "trouble" to be more rewarding that the result.

I know this has been covered to death but I am new to the Socket 7 K6III realm so can anyone link to a thread or explanation in what applications a K6 would be better than a 233MMX for example.

As far as I am aware, a K6-III-450 is faster than a P233MMX in every application. If your only interest is 3D gaming, then all I can say for my own testing is that a K6-III-450 scored 32.6 fps with Quake II (OpenGL w/Matrox G200), while a P233MMX scored 22.7 fps. If you are looking to find out exactly which games a K6-III can play, whereby P233MMX cannot play at acceptable framerates, then you will need to hunt around for this data.

The K6-3 suffers still from a weak FPU and i can't really recommend it to play 3D Games 😀

feipoa wrote:

I find working through all the "trouble" to be more rewarding that the result.

To each their own, I don't have as much patience with "misbehaving hardware" Haha! I quit using Win98 for a reason ya know, I can't stand the endless levels of buggy bugs. The same goes for hardware. I desire to keep only the best ones.