First Post...And Question about CPU Power

[Admiral Droolmaster]

New forum user, but longtime lurker. Happy to report great success with PCem so far. Lots to learn, but already finding it to be a productive prog. Almost as much fun as QEMU's latest old-Mac support. YAY!


So, when you're new, you have to think about your first post. It sets the tone for your future recognition as a fleek nerd or that lame-AF noob that got banned. Not knowing for sure which category I might land in, here is my short list of 'first questions' I thought about asking...

* When can we expect full emulation capabilities for the Zhaoxin processor?
* Why is there no ROM emulation of ENIAC?
* When can we expect full emulation of a Windows ME environment with 64GB of RAM?
* What, no 8" floppy drive emulation?
* Why can't I emulate a Prescott CPU at 100% with my VIA C3?
* Will you emulator for the VooDoo 5 support AMIGA?
* Will you allow me to link to my collection of SCSI ROMs I downloaded from roasted-penguin-spleen.com?


Instead, to make a good first impression on the assumption I might need help at some point and don't want to burn too many bridges, I ask the following:

Intel claims I will be the proud owner of a Pentium G6600 by mid-December. This processor's stock speed is 4.2 GHz, with two cores / four threads. If the purpose of the CPU is for the sole use of PCem, and I envision less emphasis on a VooDoo emulation:

* Will an i-series processor gain any additional advantage in the emulation process, even if the stock speed is less than the G6600's 4.2 GHz?
* Will anything within the i-series architecture that is superior to the G6600's architecture improve the emulation process?
* Would RAM speed play any role in the improvement of emulation performance?
* Would running the entire PCem environment in a RAMDrive provide PCem with any performance enhancements beyond the pure I/O increase?
* Is a hyper-threaded "core" less effective as an emulator engine than a physical "core"?

The idea here is to find the best place to funnel money into the project. If raw GHz is the one and only true dictator of performance...the G6600 is one of the fastest CPUs, period. But if the all the other things that make an i-series an i-series processor, or even a Skylake-X for that matter, will bring even more emulation capability, that might be worth considering.

The reason? This will be running off-grid, so the 4.2 GHz potential from only 58 watts is intriguing.

Thank you!

-Me

[SarahWalker]

Major caveat here - I have no way to reliably predict what performance you're going to get out of a given CPU. There does appear to be some general expectation I've seen that I can provide some kind of CPU recommendation service, which I can not actually do and would not even if I could; I'm not willing to give advice on how you spend your money.

Given that...

If you aren't going to emulate a Voodoo card then something like the G6600 will _probably_ perform reasonably well. The bulk of the emulation (outside Voodoo) is single threaded so the 2 core / 4 thread setup should be okay. PCem might benefit from the additional cache of an i-series chip. It might benefit from faster RAM. But it might not. Refer to my previous caveats! I don't own these chips and therefore can not provide useful information here.

RAM drive will most likely do very little.

[Admiral Droolmaster]

Thank you, Sarah!

I was a little scatter-brained earlier, but I can ask a better question now. Are there any feature sets of a processor, such as AVX or SSE4.1, for example, that you specifically targeted in your "code" that were designed to produce increased performance? My testing would suggest the answer is "no" - it's all about the GHz! It would seem that increases in performance from one generation of CPU to the next have more to do with the efficiencies gained by each successive generation's architecture and not a specific feature set.

That being said, the program is absolutely beautiful. It works. It fills the gap perfectly between hardware and virtualization. And it's far more stable than I thought emulators could be.

-Me

[SarahWalker]

PCem doesn't use anything newer than SSE2, which was introduced on the Pentium 4 20 years ago.

[Admiral Droolmaster]

OK!

If Intel delivers, I'll share some results with this new silicon, and we shall see what we shall see.

Thank you very much for taking the time to educate...

-Me

[Admiral Droolmaster]

Second question.

Is there an emulated CPU/OS/game combination that is considered a 'gold' standard for testing purposes? I never played games that were CPU or GPU heavy. So far everything I have emulated from my younger days does just fine. Research suggests that even games from the 1990's were often tuned against a specific chipset or manufacturer...

-Me

[leilei]

That's a question that's even difficult to answer with the real world variance of actual hardware. There's always a combination that a game will have a problem with.

One of the more popular common computers in the US were 95-96 Packard Bell Legends, which were often lower-end Pentium machines with little to no cache and had a Cirrus video chipset (emulated) and an Aztech sound card (also emulated) which covers a lot of the ~94-95 DOS compatibility ground, but felt obsolete going into the DirectX6 era.

Creative ISA sound cards were dominant and support for them led to a lot of compatibility in others (WSS, ESS etc). 3dfx wasn't really a "standard" but was a very popular 3d accelerator that a lot of games had to design support for before Direct3D and OpenGL implementation sorted themselves in drivers and capabilities by 1999. 3dfx cards themselves were visually different in terms of color and image quality (from both the cable and the filtering features) and can be affected by other factors (i.e. Adjusting your monitor's brightness down for S3 Trio/Virge's bright output may lead to dark 3dfx games)