AMD FX-9590 and PCem

[DevanDrake99]

I currently have an AMD FX-6300 six core processor with 3.5 GHz of speed. Whenever I try to run the CPU above Pentium MMX 233 or AMD K6-III 500, it just slows down below 40% of emulation speed. I've heard the problems were because I'm using a weak CPU.

Is it possible to run PCem at 100% with Pentium MMX 233 or K6-III 500 without dropping emulation speed on an AMD FX-9590 eight core processor with 4.7 GHz of speed? I only have a motherboard with an AM3+ socket.

[SarahWalker]

Highly unlikely, the Bulldozer architecture chips have bad single thread performance and make for a poor PCem platform.

No CPU can emulate a K6-III 500 currently. My Core i7-7700K (Kaby Lake at ~4.5 GHz) can run most stuff at higher Pentium MMX or around K6-2 266/300 speeds.

[DevanDrake99]

I've heard that some AMD Ryzen CPUs can handle the the MMX 233 emulation. I don't know all of their CPUs will run it. Intel CPUs have hyperthreading. What's the difference between Bulldozer chips thread performance and Intel hyperthread performance? How can Intel threads run better than AMD?

[leilei]

Hyperthread's just more threads on a core, it won't help much when PCem uses one thread for the CPU/sound. A Core I5 without HT will still have a much better IPC than Bulldozer (and 1st-gen Ryzen) and handles V15's PMMX 233-300 often nicely. Bulldozer even had some IPC issues vs AMD's earlier Phenom II at one point...

[DevanDrake99]

Why does the Bulldozer architecture have some IPC issues? Is IPC very important to emulate high end guest CPUs without dropping emulation speeds?

[SarahWalker]

Why does the Bulldozer architecture have some IPC issues?

Bulldozer has bad single threaded performance. It was designed for heavily multithreaded workloads, which CPU emulation isn't. Hence it is a bad CPU for PCem.

Is IPC very important to emulate high end guest CPUs without dropping emulation speeds?

Yes.

[xenaretos]

I had a 8320e CPU until recently, overclocked to 4.2 GHz. My maximum stable emulated CPU was somewhere around Mobile Pentium MMX 125. In v14 certain 3d games could go as high as 166 in 3d mode only (with sound stutter in the menus), but that was certainly not guaranteed. With the new recompiler in V15, that was no longer possible.
So, since it's the same architecture and just over 10% higher clock speed the answer to the original question is no, not unless some serious breakthroughs are made in recompiler development. The fastest guest CPU that host can handle is probably a Pentium MMX in the 133-150 MHz range.

[jznomoney]

I got rid of my AMD FX chip years ago. It was great when I first got it but intel beat the crap out of it. I was only last year when I went from a 4790k to a 2700x.

[DevanDrake99]

I bought my gaming computer from Best Buy for $500 (which was on sale) last year in 2018, and they still sold PC's with AMD FX chips. My BIOS was from 2012 despite it was sold in 2018, and they should've discontinue the parts before 2018. I would have to get rid of the AMD FX chip when I get a new motherboard, but I also have to buy new RAM with DDR4 because my current RAM is DDR3, and it's not compatible.

It's not just PCem that AMD FX chips having issues with, but the I realized FX processors actually suck in general. I have proof. https://www.youtube.com/watch?v=xxDUAJ3GqvM

[tk421]

The FX processors had a bad reputation for a long time now, at least as far back as 2012. I considered buying one more than once, but in the end it was not worth it, so I waited for the Intel CPUs to be improved to the point that PCem could run with a reasonable chance of success. The 8th gen laptop CPUs came close, but I felt the i7 9750H processor was the best value for money. I think the newer Intel CPUs, even at just 4.2 Ghz, are well worth the money.

You could probably get a good Ryzen CPU these days, and their motherboards are supposed to be good for some years to come. Personally, I think the i7 9750H is a good buy, especially if you need a laptop. If you need a desktop, the new i9 9900KS is likely your best choice.

[omarsis81]

As PCem performs better on IPC on single processors, this is where you should look at:
https://www.cpubenchmark.net/singleThread.html

[DevanDrake99]

Do I have to look at the single thread rating? My single thread rating is 1407.