Don't know where that is, but right on the faq it says up to 32 gb : http://www.iriver.com/support/faq_view.asp?fNum=582
Also on the main page of the ak100 it says up to 96gb of memory total. Not 160 gb.
Once again, maybe it does support 64gb cards, but if iriver chooses to hide that information on some random deeply found faq and not on the main page at all, that might be saying something.
All I know is that it seems like the performance using 64gb cards is 50/50 at best. If holding 64gb more music is worth having slow scans and being problematic at best . Have fun !
It's on ALOaudio's FAQ for the AK100 since they are selling it.
http://www.aloaudio.com/ak100 <---- click the FAQ tab
I know this isn't the manufacturer but why mislead people if it's not so?