Not much except for the M2.

what type dx2 -66's you got?
any sx955's

The Intel 486 DX2-66 is of some collection value if it is the L1 write-back version. It will have an &EW on the chip and SX955. Some have a big gold dye cap, some have a black dye cap. If it is not of this variety, it still has some limited scrap gold value.

The MII-333 will have some gold scrap value to it if it has a gold top. If it has a silver coloured top and has 2.2V on the surface, then this has some collection value.

nforce4max wrote:

Not much except for the M2.

Not even the M2. 333mhz is one of the most common speed grades. The 400 and 433 are the ones that get anything like good money. Even the 366 is pretty common.

366 with 2.2V is pretty uncommon though. I've run into more 400's with 2.2V.

Is the Cyrix M2 even a decent SS7 cpu, or is it just more of a curiosity?

The Cyrix CPUs had good performance per MHz (hence the PR rating). They just didn't have good FPU performance (worse than AMD per clock), and no 3DNow! either.
The SS7 Cyrix CPUs didn't exceed 300 MHZ (PR433).

I used a PR233 MII for a short while. I was satisfied with the performance, except for the FPU side.

One interesting thing is that the MII's support some P6 instructions which other SS7 CPUs don't. For example you could compile your Linux kernel for 686.

idspispopd wrote:

The Cyrix CPUs had good performance per MHz (hence the PR rating). They just didn't have good FPU performance (worse than AMD pe […]
Show full quote

The Cyrix CPUs had good performance per MHz (hence the PR rating). They just didn't have good FPU performance (worse than AMD per clock), and no 3DNow! either.
The SS7 Cyrix CPUs didn't exceed 300 MHZ (PR433).

I used a PR233 MII for a short while. I was satisfied with the performance, except for the FPU side.

One interesting thing is that the MII's support some P6 instructions which other SS7 CPUs don't. For example you could compile your Linux kernel for 686.

Unlike prior Cyrix CPUs the MII was fully i586-compatible. Back in the 90s that simplified getting a basic Linux system up and running quite considerably. Hand-rolling your own kernel for the MII arch afterward was still something I'd recommend for a perceptible speed boost, but it wasn't the headache that the 6x86 was. I can't verify that it was fully i686-compatible, but it would certainly work better on more demanding workloads than the 6x86 could manage.

Sadly the FPU was just as bad as its reputation suggests. On an MII PR433+ I couldn't turn details down low enough for Quake III Arena to run, despite the system having 256 MB RAM and a 16 MB Voodoo3 to push things along. GLQuake and Quake II engine games were pretty OK, though, and in games where the FPU didn't matter as much like Duke Nukem 3D it was pretty good value.

Concupiscence wrote:

idspispopd wrote:

The Cyrix CPUs had good performance per MHz (hence the PR rating). They just didn't have good FPU performance (worse than AMD pe […]
Show full quote

The Cyrix CPUs had good performance per MHz (hence the PR rating). They just didn't have good FPU performance (worse than AMD per clock), and no 3DNow! either.
The SS7 Cyrix CPUs didn't exceed 300 MHZ (PR433).

I used a PR233 MII for a short while. I was satisfied with the performance, except for the FPU side.

One interesting thing is that the MII's support some P6 instructions which other SS7 CPUs don't. For example you could compile your Linux kernel for 686.

Unlike prior Cyrix CPUs the MII was fully i586-compatible. Back in the 90s that simplified getting a basic Linux system up and running quite considerably. Hand-rolling your own kernel for the MII arch afterward was still something I'd recommend for a perceptible speed boost, but it wasn't the headache that the 6x86 was. I can't verify that it was fully i686-compatible, but it would certainly work better on more demanding workloads than the 6x86 could manage.

Sadly the FPU was just as bad as its reputation suggests. On an MII PR433+ I couldn't turn details down low enough for Quake III Arena to run, despite the system having 256 MB RAM and a 16 MB Voodoo3 to push things along. GLQuake and Quake II engine games were pretty OK, though, and in games where the FPU didn't matter as much like Duke Nukem 3D it was pretty good value.

What about Unreal engine games?

The FPU on Cyrix x86 processors was pretty bad, and everyone knew it back then. Before games like Quake, FPU was only important for CAD work, so you'd only buy it for its integer performance.

Still, in this age of the components of early modern computing being melted down and recycled in droves, who knows how many of those processors are still out there and alive? Might be museum-worthy in a decade or two.

For all the FPU-dominated tests run in the 686 Benchmark Comparison, a Cyrix MII running at 300 MHz will at least equate to a Pentium 233 MMX, even in Quake II. Negating the spread in time between the release of the Cyrix MII-433PR and the P55C-233, Cyrix's best socket 7 CPU was at least as good as Intel's best socket 7 CPU. The MII-433PR was also faster FPU wise than anything that IDT Winchip or RISE MP6 produced in the socket 7 form factor. All chips were, of course, were dwarfed by AMD's best socket 7 CPU.