minimum latency where anti-piracy still works is 8254. class speed is write speed not read speed, being a class 2 or 10 doesn't really matter. except for the fact that some class-2 cards we have tested have a faster read speed than class 6 cards.
AP mode isn't something you want to leave on all the time, set it on a per-rom basis. if those roms require it and having it on causes freezing then your micro sd card is probably to slow to use AP. there is nothing that can be done to fix this, its more of a limitation of the acekard hardware as the AP patching has to be done in software.
by the way that latency number i quoted came from yellow wood goblin, that isn't something i made up. i'd suggest that perhaps you want to run a benchmark on your card to see how it stacks up. recently we tested a 16gb class2 sandisk and the latency was 37700, meaning that the AP patching option users can set will never work on it.
-another world