DOSBox vs. PCem – What plays DOS games better/more accurate?

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seth
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DOSBox vs. PCem – What plays DOS games better/more accurate?

Post by seth » Sun 26 Mar, 2017 10:44 am

I know it's hard to compare those two emulators, because DOSBox doesn't require actual BIOSes and doesn't use cycle accurate CPU timings. But how good is the dos emulation on pcem right now? What's better/worse compared to DOSBox? What would you recommend?

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leilei
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Re: DOSBox vs. PCem – What plays DOS games better/more accurate?

Post by leilei » Sun 26 Mar, 2017 11:16 am


oh god a "vs" thread


PCem's good, but it's nowhere near "most accurate pc emulator" as someone has claimed many times before (and neither is DOSBox). It does have issues where DOSBox doesn't with certain games reported in this forum (Spectre VR and Zone Raiders are two). DOSbox also has problems with games PCem doesn't have (Thor trilogy anyone?) and the dosbox glide patches are really spotty or really slow (and mame derived).

For the end user that don't know/not experienced with older pc hardware and just want to play a dos game without fuss, i'd still recommend DOSBox as PCem has the rom-hunting/OS-hunting obstacle in the way of the general newbie ease of use. It'd also be the fastest option (though dosbox 0.74 does have a nasty cycles bug with recent intel processors)

If said dos game is Glide/has special content for AWE, or is one of those awfully programmed Windows/DOS hybrids, then PCem :)

If it's a Win9x game and the tricks/patches for running within modern windows don't help/work, then definitely PCem. That's assuming if the game's old enough to not have SecuROM/Safedisk/Cdillo to make the atapi emulation upset.
Note that DOSBox does not support Win9x at all, and booting win9x is considered unintended behavior and should never ever EVER be encouraged. Ignore the Youtubers.

If it's about cycle accuracy then forget about both of them. That's barely a thing for x86 emulation at all. It's a very high bar. You have CAPE to look forward to on that, currently in its early 5150 steps (and probably will stay around there given the system requirements already and the need for cycle accuracy on a system that slow)

Recommending one over the other is really about its out-of-the-box ease of use, and DOSBox is created to almost act as a dos prompt. It's like PCSX vs Mednafen, sort of. One cuts out the bios requirement and has some hi-res features to "improve" graphics (Dosbox's scalers and OpenGL Glide patch applies here), while the other requires the bios and deals with the psx as accurate as it can be with all the lovingly wobbly vertices, affine texturing and dithering it has.

DOSBox also has had at least 2-4 persons working on it at a time in the past 15 years and is well-known enough to have bug/compatibility reports constantly flowing in. Sometimes I almost feel like i'm the only one trying out games here ._. Broken games won't get fixed if they're not properly reported!

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omarsis81
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Re: DOSBox vs. PCem – What plays DOS games better/more accurate?

Post by omarsis81 » Sun 26 Mar, 2017 8:48 pm

I agree with leilei in that DOSBox is better if you just want to play a DOS game with no fuss.
PCem is more acurate in the way you run the game on a real OS (DOS or Windows 9x).

PCem is quite acurate in MIPS or integer CPU benchmarks, but I believe its FPU, RAM speed and cache are a bit out of scale.

All in all, since I discovered PCem, I don't use DOSBox anymore

PCem has most bugs fixed too

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leilei
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Re: DOSBox vs. PCem – What plays DOS games better/more accurate?

Post by leilei » Sun 26 Mar, 2017 11:04 pm

I only really use Dosbox on laptops and quickly testing random stuff these days.

ecksemmess
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Re: DOSBox vs. PCem – What plays DOS games better/more accurate?

Post by ecksemmess » Mon 27 Mar, 2017 3:45 pm

Good answer, leilei. I agree with most of what you said there.

leilei wrote:PCem's good, but it's nowhere near "most accurate pc emulator" as someone has claimed many times before (and neither is DOSBox).
I don't know about this--are you saying that there's no one PC emulator that stands head and shoulders above the rest in terms of overall accuracy, or are you saying that there is, and it's not PCem or DOSBox? If the latter, which emulator did you have in mind? If the former, that seems fair enough, given that the question of "most accurate" will of course hinge on which particular hardware elements the user wants to emulate, which software they'll be running, etc. I would still argue, however, that PCem offers the best overall approximation of the behavior and performance you'd get from real hardware, as averaged out across all of the myriad configurations and use cases one might target. In other words, for an advanced user who needs to run a wide variety of different software on emulated machines from a wide variety of different eras, losing PCem would sting considerably more than losing any other single emulator, right? That's certainly been my impression, anyway.

leilei wrote:If it's about cycle accuracy then forget about both of them. That's barely a thing for x86 emulation at all. It's a very high bar. You have CAPE to look forward to on that, currently in its early 5150 steps (and probably will stay around there given the system requirements already and the need for cycle accuracy on a system that slow)
Do you happen to know what, specifically, is preventing PCem's treatment of the 8088/8086 CPU itself from being cycle accurate? I mean, it's a pretty straightforward chip. Where do the inaccuracies there come in, exactly, and what's preventing them from being resolved?

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SarahWalker
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Re: DOSBox vs. PCem – What plays DOS games better/more accurate?

Post by SarahWalker » Mon 27 Mar, 2017 5:12 pm

Bugs, lack of time, limited interest...

robertsig
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Re: DOSBox vs. PCem – What plays DOS games better/more accurate?

Post by robertsig » Mon 27 Mar, 2017 9:43 pm

I haven't investigated it yet, but does PCEM offer the ability to offload MIDI to a hardware MIDI device? That's my favorite feature of DOSBox.

zaklaus
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Re: DOSBox vs. PCem – What plays DOS games better/more accurate?

Post by zaklaus » Mon 27 Mar, 2017 9:57 pm

robertsig wrote:I haven't investigated it yet, but does PCEM offer the ability to offload MIDI to a hardware MIDI device? That's my favorite feature of DOSBox.
You can set the host MIDI output in sound card settings in PCem IIRC. Having done that, you can use 0x330 address for General MIDI output in the machine, this should pass MIDI instruments to your host MIDI playback device.
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