ibm5155 wrote:

Since there isn't many tests comparing direcly a Pentium MMX to a K6-III

Because they're a generation apart. Comparisons of the K6-3+ versus PPro, P2, P3, Athlon, Celeron, MII and earlier K6s is far more interesting, especially if you factor in the MSRP of each (if you can find them).

From my V2 sclaing project:

I wonder how a Pentium MMX @ 300MHz (100 * 3) would hold up. Both the faster clock speed and faster bus speed should give it a fair advantage over the stock setup.

ibm5155 wrote:

Since there isn't many tests comparing direcly a Pentium MMX to a K6-III...

alexanrs wrote:

I wonder how a Pentium MMX @ 300MHz (100 * 3) would hold up.

Did you look at the Ultimate 486/686 Benchmark Comparison? Nearly all Pentium-class CPUs between 60 and 600 MHz have been compared.

The integer performance of a P55C at 300 MHz was 126.3.
The integer performance of a K6-III at 450 MHz was 253.6.
For a K6 series CPU to have similar integer performance to a P55C at 300 MHz, you can use a K6-233 Mhz (121.7). In reality, a K6-250 probably equates to a P55C-300 in integer performance. I did not test a K6-250, but a K6-266 scored 138.1.

The floating point performance of a P55C at 300 MHz was 129.4.
The floating point performance of a K6-III at 450 MHz was 229.3
For a K6 series CPU to have similar floating point performance to a P55C at 300 MHz, you can use a K6-2-266 (130.6) or a K6-333 (131.6)

The Quake II performance of a P55C at 300 MHz was 15.3 (non-accelerated).
The Quake II performance of a K6-III at 450 MHz was 20.4 (non-accelerated).
For a K6 series CPU to have similar Quake 2 results as a P55C at 300 MHz, you can use a K6-2-350 or K6-III-333.

The Pentium MMX, even at 300 MHz, is in a different league compared to the K6-III. It is much more interesting to compare a Pentium MMX to a Cyrix MII, Rise mP6, and IDT Winchip2. For floating point performance, a Pentium MMX 233 (P55C) is about the same as a Cyrix MII at 300 MHz, an IDT Winchip2 at 250 MHz, and a Rise mP6 at 233 MHz.

I know the difference is high, but I was curious about what an k6-iii+ upgrade would result in term of performance. (and also, other tests like a Pentium mmx with 100MHz fsb, usb sound card performance...)

Some weird note, idk what happened with quake 1 software benchmark, but the result from k6-III+ wasn't that big compared to the Pentium mmx one

EDIT: would a k6-iii+ 500 have a big performance gain compared to a 400 one? (like on my Pentium mmx 233 x 250, the performance on quake 2 was better, but with other testes it was minimal, and without l1/l2 cache, the performance got worse than a Pentium mmx 233)

I believe Quake and Quake II uses floating point calculations, a weakness of the K6 processor.

First I experimented with a P1-mmx, after that I tried a K6-III+ (400/66) for a longer time and now I use a PII-333.
It's over all the best machine I used for Retro-Computing. These things stand out:

1. It runs a lot of old Dos-Titles very well (though some Demos/Games will not run)
2. It runs lots of 3DFX Win9x Titles very well.
3. It also has the Power to emulate other Machines (C64/Atari/Amiga).

Overall the best pick for me.

ibm5155 wrote:

would a k6-iii+ 500 have a big performance gain compared to a 400 one?

The answer to this is in the Ultimate 686 Benchmark Comparison.

Hmm, from the quake perspective, there's almost no gain (on the point of view from the diference of a pmmx to a k6-iii)
I went to a K6-III+ because I discovered that my motherboard that I bought was a super socket 7 (I was actually just searching for some baby at socket 7 with agp).
And also, because I found the K6-IIII+ for only $10 ($5 now ;( )...

I thinked for emulating perfectly a commodore 64 you needed a Pentium 3 1GHz or a Pentium 4 2,4GHz (even If I tested on the Pentium mmx 233 an emulator that worked fine on it, but it could only make sound from the pc speaker)

PII 333 Win98se + WinUAE 0.8.8.R14 => IK+ runs perfect!