Emax

I bought the PCD-50B and have successfully formatted and used a 64MB CF card with the Emax 2. It's a PNY branded card made by Toshiba. The model number is THNCF064MMA. Per a spec sheet I found online, the card supports PIO mode 4 with a sustained write max of 1.5 Mbytes/sec and a sustained read max of 6.5Mbytes/sec. 

I have also tried using two different Transcend 2GB 80x Compact Flash cards. They both produce strange results which I assume are due to their speed. For instance, the cards format and verify but simply selecting them via the Drive Select button can cause presets to be created (00-99) with blank names. I've even seen an issue where accessing the drive causes the sample memory to disappear. Like I said, very strange. And these strange problems disappear after powering off and switching to the 64M CF card.

So, is my issue with these cards their size (2GB) or the fact that they are 80x speed? What is everyone else using? Can I use an 80x card (or faster) if it's 1GB or less or do I need to be looking for older Compact Flash cards that are 40x and under? I assume 40x works because 150K/sec seems to be what 1x is and the 64MB card I believe to be ~44x since ((6.5 MByte/sec * 1024) / 150) = ~44