Yes. You use Ctrl+F11 and Ctrl+F12 to slow down or speed up the emulation, respectively. Of course, if you'd RTFM you'd know that already. You'd also know that there is no way to accurately approximate cycles-to-MHz ratio.

Actually there is a way.
You just need a game with setup that checks your processor speed.
(Rebel Assault 2 for example)
So you can speed up or slow down dosbox to the speed you want.

Yes, I have read the manual, but have you read my question ?
I was aware that you could slow down the emulation. But that is not what I need to know. My question was is there a way to have dosbox approximately emulate a 20 / 33Mhz PC. Also note that the manual does not imply that the relation cycles / speed is variable - it states that raising the cycles over your computer capacity will result in slowdowns & that the limit is variable - that might be meaning what you said, but if it does, then it is ambiguous at best & implied - I am not a programmer or a psychic.
In the manual it says that on a 1.7Ghz, Dosbox is emulating a 386SX 25Mhz, but I imagine that is from an older version of Dosbox. What sort of emulated speed do you get on a 1.7Ghz processor (this is what I have).
So before flaming legitimate questions, read & understand them.

Loic

Thank you very much Robertmo for providing a useful & respectful answer to a simple yet seemingly misunderstood question.
Do you know of any other games that might include such a speed check ? I fear I have no idea where to find Rebel Assault 2.
Actually, I will try some Lucasarts games from around that time period & see if they have a speed check also (I am hoping the SCUMM games have this).
thanks again,

Loic

speed checks will hardly be accurate because of the way dosbox emulates the cpu, some instructions that might take the same amount of time on a real cpu can take much longer/shorter in dosbox.

Damn, I was hoping this could solve my problem...
Any idea if the 1.7Ghz for 25Mhz emulated stated in the manual is still accurate ? At least that would give me a pretty good idea.
Or maybe someone remembers how well (or poorly) Ultima Underworld II & Ultima VII play on a 20Mhz or on a 33Mhz.
Thanks for any help,

Loic

Well Ultima Underworld 1 did run like s**t on my 386 SX with 8MB Ram(i forgot how much Mhz it had, but somewhere between 16-25 for sure).
Playable if u can stand choppy gameplay & disable all textures during combat.

Ultima Underworld II is rather unplayable if u dont disable all textures all the time (making the game pointless in the process).

would recommend 486/33

why do u want to know, anyway?

Well i don't know how you can be sure what speeds you are running at but i do remember playing ultima underworld 1 and 2 on my parents old 386 (DX?/SX? not sure which it was) 33mhz computer with turbo speed button with 8mbs of ram. (hehe remember those?)

But I do know it ran fine at 66 mHz(since i nearly always had the turbo speed button on) possible not that good at 33 mHz. Not sure though. Ultima 7 ran pretty well too but Ultima 8 was a memory hogger and when a lot happened on the screen it went jerky and froze.

I know UU 1 and 2 run excellent in DosBox. In fact I've played both parts of Ultima 7 on my 2.4 gHz computer (I know it is .7 ghz more than yours that's not the point) but i do believe it will run fairly well. I've been playing most of my games at 5000 cycles so maybe running the cycles up will make it work accurately. I believe emulation depends pimarily on your computer system specs.

Ieremiou

Hi,
Thanks for the replies.
The reason I ask about this is to gauge how interesting it would be to have Dosbox for Zodiac (it can probably emulate 20Mhz full speed & maybe 33Mhz with frameskips). I am really only interested in Ultima games (ok, maybe the Wizardry series...), so I'm try to see how playable they would be.
I remember playing the games just fine back then, but I used a 66Mhz at the time, so I can't really judge how well they would run on 20/33Mhz.

Loic

Well as it is now, id say UW1 would be kinda playable (in a sick way), but not UW2. Ultima7 should prolly work, too (but i still dont like that game).

But as the authors are planning to add dynarec to dosbox, it might be much faster after that. Also the new Overlay option seems to speed up things. Also, somebody on ripa's (?) board mentioned that he managed to speed up dosbox a good deal by making his own speed optimized compile.

@priestlyboy

you sure it was 386 and not 486? Ive never heard of a 386 with 66Mhz.
Also, Ultima 8 min spec is a 486 (it did work okayish on my 486 DX 66 8MB with good dose of slowdown)

I wonder what kind of computer one needs to emulate a 200mhz? 😜 😁

Just add one "0" to the one you have

And multiply with 4

Well the point is you don't really need to emulate a 200 MHz machine, since you can easily put one together for a few bucks.

I have at the moment running

486 DX2/66 with DOS 6.22
Celeron 400 with Windows 98 SE
Pentium III 933 with WindowsME
Pentium 4 3000 with WindowsXP

So I've got all generations covered. Actually, that's not quite right... I'd need something in the Pentium 100-200 MHz range, as many games (FX Fighter for example) are way too slow on the 486 and way too fast on the Celeron 400.

Yep, indeed. I do have a P233 ,with a SB16 ISA + DB50XG (best DOS soundcombo as far as I'm concernced 😀), which works perfectly for the later DOS games. But the more games DOSbox support, the less need I have to use the P233. And someday the P233 won't be needed at all.

*sigh* That was me, btw 😊
Log in first, THEN write 😁

Psssst.... Ultima Underworld 1 and 2 run just fine with VDMSound. You don't need to mess up with speed.

VDMSound never worked for me.