That sounds like it could be the problem. Thankyou
The latest (dos) readme for advance mame says it was optimised for pentiums though, and the PC (pic attached) is Intel Pentium 166 MHz MMX, 32 MB RAM (64 MB max), 2.1 GB hard disk, 7.1" TFT display
I built my table around the machine - due to its size, and the fact I already had it. With a CF card as an IDE adaptor it flies and is certainly powerful enough to run the games I want to play. It also has no fans or moving parts.
I just wish I could compile a version of MAME to run in a dos environment

so I can implement no-nagging.
I might try and compile advance mame for a diff target...