How fast of a PCem CPU?

[speedy]

How fast of an PCem CPU can you run on a modern desktop host CPU?

For example, I'm currently using PCem on an i7-7700K and successfully have used a Pentium II 233, but I tried a Pentium II 450 and things regularly slowed down.

Thanks!

[unreal9010]

Pentium II 233 is at 100% most of the time or only in certain games or applications?
If the former then these are some really good results considering the age of your CPU.

[speedy]

My testing is far from scientific... I lowered down to a Pentium II 233 and it seems to always be at 100% with the games I've ran, but I just started using PCem a few days ago so I'd take my experiences with a grain of salt.

What would typically be the upper limit for a CPU like an i7-7700K?

[omarsis81]

You limitation to a Pentium II 233 is expected. PCem is very demanding on the processor. I have a 4790k and I can run a Pentium MMX 200 fairly good, sometimes 233 mhz

[Xanarki]

Since you've got an I7 Intel processor, you might get a little bit (but not a lot) of a performance gain by using one of those CPU Core or similar (free) programs. It'll dedicate the cores to your selected program (PCem) and also constrains other background processes.

I have an I5 7400 and on PCem v15, the difference was consistent 100% at Pentium 166mhz to consistent 100% at MMX Overdrive 180mhz. The improvements in PCem v17 allows me to reach 200mhz nowadays.

There aren't too many people around here using a 10900 or above. I'm curious to know how those handle PCem.

[xenaretos]

From AMD side, on a Ryzen 2600x the main CPU I could run completely reliably was Pentium 233MMX. As of V17, I could, however, run P2 233 with occasional hiccups in most gaming scenarios (excluding Deus Ex, among the games I tested) with a Voodoo 1, if I reduced the rendering threads to 1 (which probably lowered the performance of the GPU a bit below maximum).

With a 5600x, I can run about p2 350 with 1 rendering thread in most gaming scenarios, or 300 with 2 threads. In Deus Ex (might apply to other Unreal engine games), it's p2 266 or an almost stable 300 with 1 rendering thread.

Note that I haven't tested faster GPUs, but I think p2 300 should be more or less achievable in most cases.

[omarsis81]

Wow! Pentium II 350 now is more than I dreamt possible! We can easily reach the PII max maybe next year or 18 months

[xenaretos]

Wow! Pentium II 350 now is more than I dreamt possible! We can easily reach the PII max maybe next year or 18 months

Surprisingly enough, P2 emulation speed is quite fast. Faster than K6-2 despite it having slower performance per frequency.

[tk421]

I agree with the comments made here. I will test out some of the suggestions for improving Pentium 2 performance in PCem.

For me, the PII 233 is very fast and reliable. Pentium 2 emulation is very well implemented in v17, so it has become my de facto standard for most win98 tasks. The Voodoo3 is a huge upgrade, so most of my emulated machines are running this graphics card exclusively.

My i7 9750h typically works at 4 Ghz all core turbo, so most of time that is the benchmark speed I use to test PCem.

The big question is whether the new generation of laptop CPUs is fast enough for PII 450 emulation. I do not know how 4.5 Ghz all core turbo speed affects PCem, or even how 5 Ghz would affect PII 450 emulation.

[xenaretos]

PII 450 is not even reliably achievable on fast desktop cpus. If you are talking about Apple M1s (not even sure if there is a compiled version of pcem for those, though), probably close but not quite there yet, based on benchmark score results.

[win2k]

Pentium II 450 is 100% most of the time on my end. There are the usual issues with emulating Windows, like for example where navigating Windows' file manager will slow down PCem's emulation. That seems to happen regardless of which CPU you emulate though.

Host CPU: Ryzen 5 5600X.