I have a Sandisk Ultra II 512MB SD card in my h6315 right now actually.

I can't say that it really feels all that much faster than my regular 256MB Sandisk card.. but maybe a little. I will say that it copies data at least 4 times faster from my computer using my USB2.0 SD Card reader though. I can fill my 256MB in about 8 or 9 minutes, but I can fill this 512MB in about 4 or 5 minutes!