MAME faster on slower processor system... HELP!!

[darryl1970]

I have a MAME cabinet running on a P4 2.8ghz CPU, 2.5GB of RAM, ATI HD3850, SB Audigy. It can handle all of the classics fine, but struggles at some of the new 3d games.  I decided to pick up a Core Duo on ebay.  My p7450, 4GB, nVidia 9800gs laptop core 2 duo can play Tekken 3 at full speed and  Donkey Kong unthrottled at 1700%.  The P4 barely keeps up at Tekken, and DK unthrottled is 450%.

My issue is that the E5500 has higher benchmarks than my laptop cpu, but it plays Tekken at 60-70% (The p4 will play Tekken 97-100% on s-video out to CRT, and that really perplexes me!  Is it resolution?), and DK unthrotted is only 500-700%.  I am driving myself CRAZY, trying to find the bottleneck.  The E5500 is using the onboard realtek sound, and it maxes out at 2GB RAM.  I am running 64GB windows 7 on the laptop and the E5500.  The P4 is 32-bit XP.

Is the 2GB RAM a bottleneck when playing 3d games, like Tekken?  I added a 2GB nVidia card to free up the main RAM.  It didn't make a change.  I thought about throwing a SB-live card on, but doubt that will help.  I would have to get a new motherboard and more RAM (ddr667) in order to test the memory theory, but I am afraid that might be a waste of my time and money. 

There are SO MANY variables here, I am hoping someone on here has experience.  Is it the 2GB RAM? I thought Windows 7x64 could be the issue (the p4 is XP), but my laptop screams with 7x64, as does another core2duo desktop I own.

WHAT IS MAKING THIS SO SLOW:
MSI 945GM3-F MicroATX 775 Motherboard + Pentium E5500 CPU + 2gb DDR2 RAM (667)
2 IDE hard drives. 200GB main hard drive / 8GB Blank drive as a RAM drive for paging.
Using onboard sound
nVidia 640gt with 2GB RAM onboard

[yotsuya]

Are you using a 64-bit version of MAME?

[Haze]

there are a number of other factors between the CPUs too, the laptop one has more cache and higher FSB despite the lower overall clock.  Low memory access speed can become a significant bottleneck for MAME.