Just got my 64GB ScanDisk SDXC (yes says sdxc on the package) From Amazon today, cost $218.99
Shows up in my 2.66ghz mac mini as 15mbps transfer SDXC card
Shows up in my 27"Imac 2.8 i5 Quad as 15mbps transfer SDHC card....
Honestly I think its a software issue.
It has let me transfer 50GB of .mkv files (blu rays) and it did it in about 15 min
from my Imac to my mac mini and so forth.
And to Boot.
I just installed 10.6.4 on it and it boots up, seems to run just as fast as the 5400rpm 320GB hard drive in the Mac mini.
You da man.