DDR3@800mhz is slower than ddr2@800mhz because of amongst other things more aggressive timing available.
If you drive them with the same settings they both have exact the same latencies.
In theory you can find DDR2 modules which are specced 4-4-4
but you can also use DDR3 modules with higher speed grades and underclock them with also 4-4-4 settings. So the whole is the same at the end, right?
Much more important is IMHO power consumption as the power supply of the A500 is relative weak.
My personal opinion is this:
DDR1 is not a good option, for these reasons:
- much less memory throughput
- only smaller chips available, big chips really pricy
- higher voltage current needed. = power supply limitation problems on A500
DDR2 is OK.
o the fastest available DD2 chips are about as fast as average DDR3 chips.
- but chips are smaller or big chips are more expensive than DDR3
- DD2 needs about 25% more power than DDR3
DDR3 is ideal
+ performance is good
+ big chips are available. This means 128 MB memory easy to do with 1 single chip
+ Low power consumption.
LPDDR2 would also be a nice option IMHO.