I think it could depend on your system specs as much as the hard drive itself. If the rom is located on an external drive and you have low memory (and/or it's a large rom), it could play from the page file. If that's true, then you could be copying the game from the external drive (high lag, but good throughput) to memory (fast, but dependent on bus and drives holding the data) and then to the page file drive (if this is slow, it won't help). In any case, it's not ideal, but a usable option if required. BTW, I went through an extensive benchmarking effort this spring when setting up my file server in order to get the best possible file transfer speeds I could. I found that when comparing internal PATA, external PATA via USB, external PATA via FireWire, 10BaseT, 100BaseT, 1000BaseT, RAID5 (various combinations of locations and connections), USB and FireWire were practically identical in my setup. The speeds for internal was faster for writes, but for reads things weren't too far off for the external setups.