What is the difference between Sandisk Ultra 2 memory stick and Sony Mark 2 memory stick?

Which one is faster?


I'm planning to used it with Sony PSP, which one is the better choice?|||The MemoryStick Mark 2 certification means that the card meets certain minimum performance specifications. This is sort of like SDHC Levels -- the cards may perform faster, but they are guaranteed to be able to sustain at least their certified level of throughput.





Sony's 4 GB MS Mark 2 is rated at 4 MB/s guaranteed minimum write, up to 20 MB/s read theoretical maximum.





The SanDisk MS Ultra II 4 GB card claims a theoretical 15MB/sec Read/Write, but that will be the maximum rate -- they don't guarantee a minimum sustained write. Without that minimum write speed guarantee, there is no way to directly compare them.





(the 2 in the Ultra II model name does not mean Mark 2, it is just a model name)