Back when Windows Phone 7 launched, we witnessed a whole mess of customer confusion over the state of microSD support. Could you replace the cards? Could you change them later, or did you have to swap them before getting the phone set up? Which kinds of cards would the phones support? Eventually we learned a bit more about the state of the situation, that the operating system required cards with exceptional random access performance, rather than the simple throughput measurements typically used to classify card performance. Microsoft started work on evaluating microSD cards for meeting performance requirements, and we expected to see sales of WP7-approved cards begin. After a bit of a false-start in January, it looks like those cards are finally here, with 8GB Sandisk models sporting the Windows Phone logo popping up in AT&T stores.
With its easily-accessible microSD slot, the Samsung Focus is the clear target for these accessories. While other, non-approved microSD cards may work just fine, there’s a lot to be said for the peace of mind afforded by officially-approved hardware. Unfortunately, the cards are quite expensive, with 8GB running you $32; other 8GB microSD cards with the same Class 4 speed rating can be found for less than $15 a pop. With those, though, you run the risk of those random access times being too slow for the card to keep up with WP7.