Does Readyboost mitigate a poor hard drive write latency? I have an ultraportable laptop that uses 7mm 2.5" drives. Unfortunately, this limits me to the Hitachi 7200rpm 320GB or the Hitachi 5000rpm 500GB (the 7mm Seagate drives are out of production due to natural disasters in Thailand). I want capacity so my iTunes library can reside on the internal HDD instead of carrying around an external drive. The storage review dot com review for the Hitachi 5000rpm 500GB (Z5K500) was crushing. Most importantly, the write latency of the Z5K500 is terrible, and that will impact the overall performance feel of my laptop. Does Readyboost address poor write latencies? I know Readyboost addresses reads - that's why it preloads the Readyboost cache - but does it cache writes? I don't want the performance hit from the Z5K500. If Readyboost won't help, I'll get the 7000rpm 320GB model instead.