I suspect the 66MHz bus really kills the K6-2 as all the L2 cache is on the motherboard.

if you could get a K6-3 to work that might work better as it has cache on the CPU.

Also FPU wise I suspect the pentium 233 and a 400mhz k6-2 wouldn't be dissimilar. A 100MHz FSB would help the K6-2 though.

Edit: I am in the process of building a 100MHz K6-2/3 system, so when done I will benchmark.

Even on a 100MHz FSB, K6-2 CPUs are slow. Don't expect any miracles, the Pentium 2 and 3 were quite a bit faster than the K6-2 and K6-3 processors in games.

Not sure the K6-3 will work in the adapters made for the K6-2. I know there is a tailor made adapter for the K6-III from Powerleap, but that one is impossible to find.

Yeah, my suspect is also the slow bus and the lack of L2. I'm not sure the K6-2 can communicate with the L2 on the board through the adapter.

Anyway, lackluster results doesn't matter that much. It's just me pimping it out kinda, and also having wanted to test it out since 1999. The compaq is more for just fun and pre-1998 games. It's so hopeless to upgrade and work on that I have started to love it. I will take some photos and post here soon. I'm building a 440bx system with a P3 for the games that require the increased performance.

i assume that mmx-233 is comparable to k6-3-266, or k6-2-333 due to its lack of on-die cache, so your k6-2-400 is indeed not much faster, especially that its running at 66fsb.
its also well known that k6 at 6x clock has much lower efficiency than 5.5x. my test is that k6-2+600 yields no more than 2% improvement over 550, despite a 9% clock increase. you can try your k6-2 at 366 and see if its the same.
and dont just stick to 3d benchmarks as it can involve more issues, including vsync and others. try superpi first as its a pure fpu+ram test.

You can get a K6-3 pretty cheaply and I think it should work, it is the same as the K6-2 but with cache on the CPU.

Get one with the correct voltage (there are a few different ones) and I wouldn't be surprised if you got 20-30% increase in speed, as the 66MHz FSB doesn't matter as much with the K6-3.

A few things to keep in mind.

Don't worry about multiplier limitations on your motherboard. You can have just about any multiplier you want by bridging certain CPU pins on the bottom of your motherboard.

You can get K6-2+ chips to work on pretty old motherboards by getting a 3rd party BIOS upgrade. There is a website out there devoted to K6+ chips. I tested such a BIOS on an Asus VX97 and K6-2+ 550 with very good results. Yes, this motherboard had a VX chipset.

The real limiting factor is if your motherboard supports low enough voltages for the later generation chips.

noshutdown wrote:

try superpi first as its a pure fpu+ram test.

I did the game benchmarks since that is the most important to me. When I tested in Wintune 97 I got a much higher score with the k6-2 400 mhz. Then again these benchmarks test the CPU more separately rather than the whole system.

You can get a K6-3 pretty cheaply and I think it should work, it is the same as the K6-2 but with cache on the CPU.

Get one with the correct voltage (there are a few different ones) and I wouldn't be surprised if you got 20-30% increase in speed, as the 66MHz FSB doesn't matter as much with the K6-3.

The voltage is no problem as I can change that on the adapter itself by either moving dipswitches or jumpers. It works independently from what the motherboard is trying to feed it (2.8v). The main issue is that the K6-3 will only work on the Spectra adapter and there the CPU is so stuck in the adapter that I do not dare to use more force to get it loose at the moment. If I had another one as backup (or a Powerleap with no CPU in it) I could give it a shot.

A few things to keep in mind. […]
Show full quote

A few things to keep in mind.

Don't worry about multiplier limitations on your motherboard. You can have just about any multiplier you want by bridging certain CPU pins on the bottom of your motherboard.

You can get K6-2+ chips to work on pretty old motherboards by getting a 3rd party BIOS upgrade. There is a website out there devoted to K6+ chips. I tested such a BIOS on an Asus VX97 and K6-2+ 550 with very good results. Yes, this motherboard had a VX chipset.

The real limiting factor is if your motherboard supports low enough voltages for the later generation chips.

The motherboard in the Compaq is completely proprietary. It is non-ATX / AT form with everything integrated. Multiplier is also not a problem as that is set by the adapters through changing the jumpers and dipswitches on them to whatever you want. This overrides the motherboard. Maybe bridging some CPU pins would in theory work, but I do not have the skills or knowledge for that.

Again, the BIOS used is specific for this manufacturer (the bios is called Rompaq) and it sucks. There are very few options available to you and no way to upgrade it as far as I know. Also I can not change the volt on the motherboard itself, meaning the K6 will be getting 2.8 volt instead of 2.1-2.2 as they require. Add to the multiplier which is locked at 1.5 to 3.0 and running the K6 directly in the socket is very unlikely. It also refused to even lit the screen when I tried the K6 in the Turbochip.

This is the website about BIOS updates to support the K6-3/2+. If it is not on this website, and if Jan is not too busy, he may even modify your BIOS for you.

http://web.inter.nl.net/hcc/J.Steunebrink/k6plus.htm

I am generally not too worried about the voltage a motherboard supports as most onboard voltage regulators can be modified without too much head scratching. The pdf contained in the thread below is a good starting point,

Modifying your motherboard's voltage regulator for overclocking

Most motherboards have undocumented FSB and multiplier settings that you can experiment with. This may be less true for non-standard motherboards, such as those from Compaq, Dell, Packard Bell, etc.

One thing you didn't mention, so I am not sure if you're aware of it. Especially Quake 2 gets a great boost from using the 3DNow enabled patch (which might even have it's own executable - I don't remember that from the top of my head).

Did you try those?

I found my old written notes, which say that I got 67.2 Fps with my (then) K6-2 OCed to 380 in 1024x768 with Voodoo2 SLI - up from 46.4 fps without 3DNow. My Winstone 97 score back then seemed to be 53.6 with a Riva TNT as primary video card if that's any help.

It's the bus that kills these CPU upgrades. You really would have been better off putting the upgrade money towards a motherboard that supports a higher bus speed back then than putting a fast CPU in an old motherboard. You might have even been able to transfer many of the original parts from your old system to the new motherboard until you could afford to upgrade them.Then there's the issue of voltage compatibility requiring a socket interposer that you might not have had to deal with if you had just bought a newer motherboard in the first place. The only problems then were manufacturers that used proprietary parts like cases and power supplies that wouldn't work with industry standard motherboards. If you had one of those you were pretty much screwed but once you had a suitable case and power supply, you could keep reusing those, too. It's fun to play with that stuff now if you can find the parts for good prices, but back then it probably wouldn't have been worth it.

[GPUT]Carsten wrote:

One thing you didn't mention, so I am not sure if you're aware of it. Especially Quake 2 gets a great boost from using the 3DNow enabled patch (which might even have it's own executable - I don't remember that from the top of my head).

Did you try those?

I found my old written notes, which say that I got 67.2 Fps with my (then) K6-2 OCed to 380 in 1024x768 with Voodoo2 SLI - up from 46.4 fps without 3DNow. My Winstone 97 score back then seemed to be 53.6 with a Riva TNT as primary video card if that's any help.

I didn't know there was a 3Dnow patch. I downloaded it and installed it. Zero improvement. My guess is that the system can't use the 3Dnow as intended. I made a Youtube video of the benchmark:
http://www.youtube.com/watch?v=l_5Qk2VXVAQ&feature=youtu.be

It's fun to play with that stuff now if you can find the parts for good prices, but back then it probably wouldn't have been worth it.

I agree, back in 1999 I didn't know much about computers and I though this would be a better upgrade than having to buy a new mobo, power supply and case (rest of the parts could be transferred). Very glad now that I didn't do that, but saved my money for a new 440BX system. I guess the companies behind these upgrades were targeting people with little knowledge. Now as you say, it's fun to play around with. I payed 2 dollars for the Spectra and 10 for the Turbochip, so not the biggest loss and the computer is a bit faster in games, and noticeable faster in Windows 😀

Yep, the bus speed must be it, you can check my thread where I upgraded my Pentium pro 200 to a Pentium 2 Overdrive 333, my Quake 2 scores increased by 10% at 1024x768 which is about the same increase you got, interestingly you score are probably no different even considering the beast of a graphics card my machine runs (Geforce 6200 PCI), perhaps the pci bus is also a detriment to potential peformance vs AGP?

Pentium(PRO) 2 Overdrive 333 BEAST

vetz wrote:

I didn't know there was a 3Dnow patch. I downloaded it and installed it. Zero improvement. My guess is that the system can't use the 3Dnow as intended. I made a Youtube video of the benchmark:

did you choose the "3dnow 3dfxgl" renderer instead of the default "3dfx opengl", after you download the patch?
i have this patch and it yields only 5% improvement with both nvidia and ati cards, and colors become ugly, i guess its only good for 3dfx cards.

noshutdown wrote:

vetz wrote:

I didn't know there was a 3Dnow patch. I downloaded it and installed it. Zero improvement. My guess is that the system can't use the 3Dnow as intended. I made a Youtube video of the benchmark:

did you choose the "3dnow 3dfxgl" renderer instead of the default "3dfx opengl", after you download the patch?
i have this patch and it yields only 5% improvement with both nvidia and ati cards, and colors become ugly, i guess its only good for 3dfx cards.

Crap... No 😒
New benchmark gives 57.4 fps. Nice improvement!

Are there any other games with 3Dnow patches? Or that has them built-in?

EDIT: I found an uofficial one for Half-Life! Gotta do some tests on that game 😀

Try Quake3 (demo is fine for benchmarks) I would be interested to see how it goes 😀

EDIT:

I just got my K6-2 machine going

AMD K6-2 350MHz with 100MHz FSB
IBM Pro283 Motherboard (SIS 540 chipset)
128MB Ram (running at 133MHz)
8mb shared memory SIS300 video card (does OpenGL!)
Windows 98se
40gb HDD
Voodoo 2 12mb PCI (FastVoodoo 4.6 Drivers)

I don't seem to be able to get Quake 2 to do a time demo correctly, only the demo version.

Quake 3 Demo - 3DFX Mode - 640x480 (with default graphics settings). 22.5FPS.

I have a K6-3 400MHz on order which I will try when I get it.

what version of quake3 do you have? if you have v1.32(the newest version) then i suggest you to run my "fake-nv15demo" to put some more load to your cpu than that built-in demo. i recorded it because the original nv15demo was made for some old versions of quake3 and won't play on v1.32.
you need the nv15 map to play this demo, download it here(original nv15demo is included, would probably play on v1.17):
http://alt.3dcenter.org/downloads/quake3-nv15.php

FYI

I upgraded my K6 machine:

K6-2/350MHz
Quake 3 Demo - 3DFX Mode - 640x480 (with default graphics settings). 22.5FPS.

K6-3/400MHz
Quake 3 Demo - 3DFX Mode - 640x480 (with default graphics settings). 35FPS.

Much quicker than I thought it would be.

vetz wrote:

Are there any other games with 3Dnow patches? Or that has them built-in?

EDIT: I found an uofficial one for Half-Life! Gotta do some tests on that game 😀

For games using non-propretary renderers, it's just a matter of which version of Direct3D or OpenGL is used and whether you have the appropriate DirectX or OpenGL drivers installed to support 3DNow!.

Anything DirectX 6 or higher should have 3DNow! support, not sure about when OpenGL started supporting it.
It's a similar situation as with SSE support, except 3DNow! came out first and got a handful of proprietary patches early-on.

How much improvement 3DNow provides varies by game though. (from around 30% to nearly double the speed -with GPU not a bottleneck)

With OpenGL, it's the ICD that has the SIMD optimizations. In order to benefit from API optimizations, the game needs to use API features like the internal geometry processing.

Really the game itself needs to thoroughly use SIMD for it to matter in a tangible way. The most aggressive effort was AMD's Quake 2 patch AFAIK. They did game engine optimizations, a Voodoo2 ICD and an optimized software renderer too.