DMA stands for Direct Memory Access; it is a way of allowing a device to directly access memory blocks without the involvement of the Central Processor Unit. This reduces the processing overhead and in the case of the Acekard, reduces lag associated with MicroSD data transfers.
Older builds of AKAIO featured different DMA modes. The software informed the user as to which DMA mode was working based on the color of the "Loading..." text; Yellow is an improved DMA mode, Green was the Quick-Save DMA mode which was previously the default in AKAIO v1.4 - v1.6, and Red was the original DMA mode. Before Red was used for the original DMA mode it denoted a no-DMA mode, where DMA was turned off. As of v1.8.5 the new DMA yellow mode has been made default, this mode is significantly faster than the previously tested DMA modes. The older DMA modes have been removed and are no longer supported. There is currently no way to turn off DMA, it is on permanently.
Loader encryption was added starting with AKAIO 1.6RC1 as clone/fake teams with AK2i based Flash Kits were using AKAIO as their firmware. This added encryption increased loading times until the yellow DMA mode restored loading times to those of AKAIO 1.5.1 while maintaining encryption levels. Due to AP patching and other internal patches loading times may be slightly increased depending on user settings, microSD speed, etc.
For games that are problematic with DMA mode, please make sure to first update the loaders to the most recent version. Updated loaders can be found at the Loaders Download Page or via Wi-Fi Update from within AKAIO. If you notice a problem, even with the latest loaders, please visit the AKAIO ROM Compatibility Page. Add your problematic game as needed by following the on-site instructions. You should also need to visit the AKAIO Forums and submit a proper bug report, please read the rules and previous bug reports before submitting your own.