I've only noticed this in AceKard 2i. I have both the retail cart and CycloDS. From playing the Retail Cart, I know what to expect, and it has never lagged on CycloDS. Ever. But, I notice a signifigant (Well, to me, at least) slowdown on AceKard. The graphics are choppy and things like cycling through the Pokédex are a lot slower. Also, when my character runs, it looks really... Laggy. I'm using AceKard 2i on a DSi, Firmware AKMENU 4.16, Sandisk 8 GB MicroSD Card.