Well JSW, I playbacked my inp on cosmica and I found that....(posted 9500 days ago)It playbacks well.
So what is your problem? Try it and You will see it is the truth. If not, e-mail me.
About speed, I play at full frame-rate with my p2-333 on the major part of the games but I can not test all the version of mame to see the hardest.
In any case if you think there are some inp of mine that doesnt' playback please say it to me so I will reverify it.