What options do you tweak in MAME to speed a game up?

[BadMouth]

The couple threads on benchmarking have me wondering.

What settings in MAME do you tweak in mame to wring out a little extra speed when a game is almost running at full speed?

[RayB]

Everything "extra". Graphics effects, sound quality ...

[shan1784]

Are you speaking of setting in the mame.ini / command line options? If so I'd be very interested to know this as well... I've been reading up on all of this but I still don't know what really makes a difference.. Everything I've done really hasn't made a huge difference in the performance as of yet...

[RayB]

If you do it through MAME32's UI interface, it's easier to get a feel for what options do what and have an impact. Then when you're satisified, you can look at the INI file itself and see how they are all configured.

[DaveMMR]

I know changing the sample rate for me sometimes help enough to stop any "stuttering", but I'd be curious to hear some more suggestions as well...

[nitz]

Something that will work on some games is to enable cheats and then underclock the processor(s). Search the forum for "underclock" and I think you should find a few threads from a few years back that tell you how to do this. I would try everything else first as doing this can sometimes cause problems with sound or instability, but this can help get borderline games up to full speed. I remember getting Killer Instinct running full speed on a pretty crappy computer using this method.

[BadMouth]

I did some tinkering yesterday using MAME Plus.  Changes were made specific to a game, so I didn't screw anything else up.

Changing the video from GDL if it was set to that and unchecking all types of video filtering made a slight improvement.
Unchecking hardware stretching and substituting scaling=2 for it seemed to make a small gain too.  (I never figured out how to change my monitor resolution to fit the game).  I'm not really sure how this would free up CPU since I thought these were things the graphics card handled, even if the CPU is handling the initial drawing.

Increasing windows audio latency got rid of some sound skips, lowering the sampling rate didn't seem to hurt anything and may have increased speed.
I read somewhere that disabling all unused input devices will actually make a small improvement...couldn't hurt?

Honestly, I don't really know much about the settings or which ones would use less resources than the other.
I was hoping someone with a better understanding would be able to give some insight.

Any improvement I got was nominal and subjective.  At most, I may have gotten a 5% increase in the game I was working with (California Speed on a 3.2Ghz Athlon II - averages 75-85%.  Playing without sound ruins it for me worse than running slow)

The one victory I did get was that I discovered one of the clones of Tekken 3 runs a LOT faster than the parent (the other clones are glitchy).
This was on a 2.9Ghz Athlon.  It ran, but had some sound skips and occasional slowdown.  The clone runs 100%+

This was in MAME 1.35 (or 1.36?).  They could have changed by now.

[Turnarcades]

Everything "extra". Graphics effects, sound quality ...

+1 to this. Disable triple buffering, all graphics filters, stretching etc. and try changing the frameskip to a set amount rather than leaving it at 'auto'. With a set frameskip of 2 or 3, you may not notice that occasional slowdown where 'auto' would increase the frameskip on heavy demand sections, and you soon ignore any missing animation frames. This method is also effective on mobile emulators, like MAME on my iPhone.

Oh, almost forgot - on lower-spec systems, increasing RAM helps a lot. Not sure if it helps on decent CPU's or decent graphics cards, but it's worth a pop.