When I built my arcade cabinet in 2007, I used the following:
MaLa 1.0 R9
MAME-Plus (I don't know the original version, I've got .159 on it right now)
HP Pentium IV
Windows XP
27" flat CRT VGA
It all runs great, smooth, fairly attractive (no animations).
Now that it's 15 years later, I've decided to upgrade the entire system. I've already built a new control panel with the additions I wanted (A couple of spinners and an analog joystick).
I plan to use Attract Mode with MAME .251. I've been able to download a complete ROM/CHD set for .251, and will be going through and choosing what games I want to make the final cut (The GUI I'm using for MAME says there are 12,189 working games). Obviously much of this is stuff I have no interest in, and duplicates (clones).
Finally to my question, if I want to be able to run some of the more modern games like Big Buck or GTFORE series, how much of a CPU and or GPU will I need?