If we look at the HDtach results one thing is obvious, the 5400-rpm harddisks are no match for any of the 7200-rpm harddisks. The difference between the fastest and slowest disk in this roundup is a massive 64% (40618/24755). If we however look at the scores for 5400 and 7200-rpm averaged, the 7200-rpm harddisks are on average 31% (38513/29339) faster. A clear-cut conclusion you might think, 7200-rpm harddisks are faster, period. Unfortunately we couldn’t be further from the truth. HDtach is a sequential benchmark and as such is useless if you’re looking for real-world results. It simply measures the maximum throughput in Kb/s across the platters, working from the outside in. In a real-world situation the harddisk will never read or write data from/to the platters sequentially but rather scatter the data all over the platters. Nevertheless HDtach gives a good indication of what the harddisk is capable of; a good reference to compare to the real-world benchmarks.