Author Topic: DOSBox works too fast  (Read 3256 times)

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Offline Leo

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DOSBox works too fast
« on: February 05, 2013, 04:50:26 AM »
Running 'Lemmings 2' with DOSBox doesn't goes well. It's too fast, even level clocks is too fast (maybe about... 15%). It is playable, but it's obviously faster then it should be. I don't know what to do with this anymore. Nothing I try to do with configuration can't set the speed to the right one. And the problem is not just mine, it works the same on the uploaded Youtube videos from (at least) two sources. So, if anyone have some idea how to fix this problem, please tell me.

Offline Clam

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Re: DOSBox works too fast
« Reply #1 on: February 05, 2013, 05:18:44 AM »
This seems to be a problem with the version currently on Abandonia. This version seems to be different to the one I used to have - for one thing, it includes the "fixed" executable "l2-fix.com", which I don't think it did before. Maybe someone has an older version and can compare? (Also, I'm sure I had it on my PC, but it's mysteriously vanished... spooky)

You could try turning down the CPU cycles (Ctrl+F11). That way, your computer gives less processing power to DOSBox so it can't run as fast. Note that this is more a workaround rather than a true "fix" :)

Offline Leo

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Re: DOSBox works too fast
« Reply #2 on: February 05, 2013, 03:29:48 PM »
I can try to find some other version of the game, but I don't think this will help. l2-fix.com is just suppose to remove protection (isn't it?). And even demo version of 'Lemmings 2' is too fast. Lowering CPU cycles can't help much. It's true, game slows down if there is not enough CPU power, but then it's very sensitive to the number of Lemmings on the screen, and even scroll of the screen is completely ruined.
Similar 'speed' issue is present in some other versions. On the Amiga screen refreshing rate (PAL/NTSC) can be changed by pressing 'Tab' and that also affect speed (but still, it's never as fast, as PC version). Also SNES version has a different speed (NTSC and PAL version cartridges).
Looks to me like I should 'explain' to the DOSBox that game screen refresh rate is to high. How to set screen refresh to the lower value (not the real one, just to force the emulator to act like refresh rate is lower)?

Offline ccexplore

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Re: DOSBox works too fast
« Reply #3 on: February 05, 2013, 08:51:51 PM »
Hmm, I'll admit that when you point it out like that, DOS L2 does feel pretty fast, but I don't have a means to run L2 outside of DOSBox at this point.  Are you basing your observation on merely the fact that the timer speed doesn't match the real world (ie. 1 game second not equal to 1 real second), or have you been able to experience DOS L2 outside of DOSBox emulation?

I'd think that if the problem (if it's indeed a problem) is related to the emulated screen refresh rate, it would affect a lot more games in DOSBox than just Lemmings 2.  Unfortunately I don't think there is any way right now in DOSBox to tweak the emulated screen refresh rate.

Offline Leo

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Re: DOSBox works too fast
« Reply #4 on: February 06, 2013, 12:28:18 AM »
As I remember playing 'Lemmings 2' (long time ago, maybe I am wrong) from DOS, it was 'normal'. Anyway, PC DOSBox version is faster then any other version. As I said, SNES NTSC cartridge, also runs faster then PAL cartridge (talking about using ROM image on the emulator).
Does it really matter where is the source of the problem? Slowing down and speeding up, works fine with MAME, why there isn't (or there is? that's what I asking here) a way to do the same thing proper with DOSBox? My goal is not to find excuse for the improper work of that game. I am trying to make it work as it should, but I am not very succesful (obviously) in this, so I asking for the help of you guys. Solution doesn't need to be related with screen refresh. In fact, I will be happy with any solution (if there is any).
About other games in DOSBox, I don't know. DOSBox is far from perfect, I can't tell is the speed right in 'Doom'. Maybe it is, maybe it isn't. And for example, 15% faster game play can hardly be a problem in 'Monkey island' or 'Legend of Kyrandia'.

Offline ccexplore

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Re: DOSBox works too fast
« Reply #5 on: February 06, 2013, 04:24:36 AM »
Well sorry, I don't know of any DOSBox configuration settings myself that would help in this case, and it'd hardly surprise me that there aren't any, considering that DOSBox lacks many features (eg. savestates) that are common in most other emulators of other things. :-\ I suppose you'll just have to get enough people to complain about it so maybe they can try to fix it in some next version.  As I said, I'd think the problem will probably affect many games besides Lemmings 2.  In the meantime, just make copius use of pausing (P on the keyboard for Lemmings 2) to get through the game. ;)

Incidentally, the NTSC/PAL speed difference (completely unrelated to DOSBox of course) you alluded to may be fairly common in the world of consoles.  It's due to NTSC having a 60Hz screen refresh rate compare to PAL's 50Hz.  Depending on the game and other factors, it may just not be worth the effort to reprogram the game to compensate for the difference (especially with a fraction like 6/5 rather than some simple integer multiple), especially old games where memory and CPU resources are already limited.

Offline Leo

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Re: DOSBox works too fast
« Reply #6 on: February 06, 2013, 12:58:55 PM »
Oh no, as a master Lemmings player I don't need help of the pause key at any speed rate (just joking). I just bothers me that game can't work right.

I know there isn't NTSC/PAL issue on the PC (unless while it's not connected to the TV), but I have the same speed problem with 'Outrun 2006: Coast to coast'. It's OK if I let the game use 60Hz refresh rate, but if I change that to 80Hz game runs (significantly) faster (again, even the clock counter). Obviously that game is affected with screen refresh rate. Of course, that's not related with DOSBox, it's Windows game using DirectX.