I've searched everywhere. But I haven't found out the answer to this question. Hopefully, someone can help. That is - when does the GP2X's Device USB Port operate in High-speed USB mode? I've done some testing on a high-speed USB host port on my computer and it seems that I can only get high-speed USB speeds when using a 1GB SD card. If I use a 2GB SD Card (and I've tried many), I only seem to be able to get full-speed USB. In addition, if I try transfering using the GP2X NAND memory, it also only operates in full-speed. Has anybody else noticed this? Has anyone tried with a 4GB or higher SD card? Finally, what were some of the transfer speeds you were able to achieve when you were able to operate in high-speed USB mode?

The usb client port is always in full speed USB 2.0 mode. But the CPU, SD card and NAND are bottlenecks.

If you're unhappy with the GP2X's transfer speed you could just get a card reader.

Thanks. When you say "full speed USB 2.0 mode", you mean "high speed USB 2.0 mode", right? Have you tried all three settings I've talked about - 1GB, 2GB SD cards and NAND memory and got the same transfer speeds? Yes, I already have a card reader. But when I bring my GP2x to a friend's house, most of the time they don't have a memory reader and even if they do, it's only a slow full-speed one.

Yes, I mean high speed (see NetChip 2272 Datasheet). Its so confusing that "Full Speed" is slower than High Speed.

You might want experiment with different sector sizes when formatting. Also take note that 1 large file copies faster than several small ones.