DOSBox - number of CPU cycles for various games

[Revenant]

So I have recently been playing the first Ultimas in DOSBox and noticed the uneven system requirements between different Ultimas. For example, 1000 cycles is quite good for Ultima V, yet in Ultima II this seems too much as the auto end of turn apparently happens too frequently. That being said, have you ever experimented with various numbers of CPU cycles for different games and found some optimum values? Maybe you even did some research as to what number of CPU cycles recreates the original experience of a game on its original hardware? If so, post your findings in this thread!

 

[spekkio]

AFAIK it depends on the speed of your CPU, so 3000 can be good for you, but not for a fag with slower/faster CPU.

In before somebody proving me wrong.

 

[Revenant]

AFAIK it depends on the speed of your CPU, so 3000 can be good for you, but not for a fag with slower/faster CPU.

If the "cycles" variable indicates how many instructions DOSBox tries to emulate per second, this variable should be system-invariant, if I understand correctly.

 

[Zed]

Moving to General Gaming.
I've never changed CPU cycles in DOS box. Maybe that's why Wasteland keeps crashing on me.

 

[JarlFrank]

Sometimes it lags, sometimes it's too fast with the default 3000 cycles or whatever the default is. For most early 90's games I use somewhat around 6000 cycles, and I still do this with my new CPU which is quite a bit faster than my old one and the performance is the same, so it's probably system-irrelevant. I haven't played anything on my netbook in a long time but I remember setting the cycles for M&M World of Xeen to about the same amount as I use on my desktop, so yeah.

 

[Revenant]

For most early 90's games I use somewhat around 6000 cycles <...>

Yup, pretty much the same here even on my old outdated Celeron M notebook. For Dark Sun, I remember setting cycles to 7000 or so. However, Black Thorne seems a very demanding game and requires about 13000 cycles to run fluently.

 

[Excidium]

Depends on the system and also the game. Mess around with increments of 1000 until you find an amount that makes the game run well.

Some will always run poorly, like Dark Sun. It's always either too slow or too fast for me...

 

[sgc_meltdown]

Syndicate Wars on glorious ingame 640X480 high res: 120,000 cycles

That's for the actual missions to run smoothly, but animations and those little briefing cutscenes play very quickly on the management screen and you need only wait about two seconds for the intro to start on the login screen

 

[Astral Rag]

Bullfrog


I'm using the same setting for SWARS, it runs great but the frame rate does plummet temporarily when I level buildings.

OP are you aware that you can adjust cpu cycles in realtime with ctrl+F11 and ctrl+F12?

 

[Revenant]

Of course I am aware of that, as I am also aware that you can set cycles to Max. to make full use of your CPU. I am specifically referring to games that rely on CPU cycles to determine time (like old Ultimas) and thus may run too fast if the CPU cycles are set too high. I guess back then programmers couldn't use the system clock that easily in their software, otherwise devs of those days deserve a punch in the face.

 

[Thrasher]

This is what I have used recently with excellent results:

- XCOM UFO Defense - auto limit 10K
- Master of Magic - 10k
- Master of Orion - 10k
- Pool of Radiance - auto
- Curse of the Azure Bonds - auto
- Secret of the Silver Blades - auto
- Pools of Darkness - auto
- World of Xeen - 7k
- Ultima 7 - 7k

But it also depends on the scaler and renderer you choose, I think. Probably the sound emulator, too. They have to be given enough time to do their job between each cycle, which depends on your CPU/GPU.

 

[Sigourn]

Testing out DOOM, Eye of the Beholder, The Magic Candle on DOSBox, I have to ask a question: how do you tell a given speed is the accurate speed?

 

[oddech_wymarlych_swiatow]

Testing out DOOM

Running Doom through DosBox in era of source ports is beyond me, if you want to keep original experience intact just use Chocolate or Crispy Doom.

 

[ebPD8PePfC]

Testing out DOOM, Eye of the Beholder, The Magic Candle on DOSBox, I have to ask a question: how do you tell a given speed is the accurate speed?

Assuming you're a normal user who just wants to play the game and doesn't care too much for accurate emulation, use ctrl + f11 and ctrl + f12 to change the cpu cycles until everything seems to be working properly.

Aiming for an "authentic" and accurate emulation of the cpu is pointless to a degree, since that didn't really exist back in the day. Games ran at the speed of the CPU, and once newer models came out the games broke down since they ran too fast. A Turbo button was added to solve this issue, that told the CPU to run at a speed of 4.77 MHz, which was the standard game devs used. You can find guides online how to emulate this speed:
https://www.dosbox.com/wiki/4.77_MHz
But I doubt it's worth the trouble.

 

[oddech_wymarlych_swiatow]

DOS emulation is shit anyway, just play on period correct hardware.

 

[Boleskine]

Vogons and the DOSBox website are the best places to check settings/configurations for old games.

 

[Goi~Yaas~Dinn]

DOS emulation is shit anyway, just play on period correct hardware.

This is the only true answer. DOSBox has done everything possible to:

1. Be just good enough to discourage a true competitor.
2. But not good good enough to obviate the need for one.
3. Have a core so shitty (a la ZSNES) that it is pretty much impossible to properly refactor.
4. Adopted only the very worst practices of FOSS, thereby becoming user-hostile by default.

I'd say it was the ePSXe of its field, but that would actually be doing ePSXe a disservice.