Thanks to this thread and its contributors, I just ordered an A-Data 4gb microsdhc class 6 off Newegg. I'll update when I get it and try it with the CycloDS!
Ninji said:I have a Transcend Class 6 4Gb card with my cyclo and I couldn't be happier. The thing works like a charm, haven't seen one slow down yet in any game, no less the castlevania games.

There aren't really any issues with slowdowns in the Castlevania games anymore. There is one particular issue with CNinji said:I have a Transcend Class 6 4Gb card with my cyclo and I couldn't be happier. The thing works like a charm, haven't seen one slow down yet in any game, no less the castlevania games.

What country are you in? If you're in the US, check out newegg:qwsed said:Can someone please tell me the best place to buy an a-data card? (8 gb class 6)

laci.laplante said:Newegg just graced my inbox with fantastic news. The 4 gig A-DATA card has been nominated for a customer choice award. I'm glued to my screen to find out what it will be wearing to the ceremony.
Laci