Agreed, appart from the A530 mounted fast RAM, you have a 32-bit CPU connected to a 16-bit system bus. That's your bottle neck right there IMHO.
The stock A1200, with it's 32-bit bus (and about twice the CPU clock speed) is supposed to be about 4 times faster than a stock A500 with it's 16-bit bus. I expect it is similar for an A500+.
