We tested HD Tach with the benchmark's full variable zone size setting.
HD Tach's sustained transfer rates give us a sense of what these drives can do in a straight-line drag race. Frankly, there isn't much to see here. Unlike in our real-world file creation, read, and copy tests, the 5,400-RPM drives are evenly matched. Only 1MB/s separates them. As one might expect, the 7200.4 is faster than the 5,400-RPM drives, but only by 17-20%. The faster Momentus actually has a 25% spindle speed advantage.
Burst transfers come straight from cache memory, so spindle speeds don't factor into the equation at all. Here, the 7200.4 actually turns in the worst performance of the pack, failing to reach even 170MB/s. The rest of the mechanical field is spread between 230 and 249MB/s, with the Travelstar leading the way.
The 7200.4's higher spindle speed gives it a clear mechanical latency advantage over 5,400-RPM drives, but the Momentus' random access time is just a millisecond faster than the Scorpio Blue. Quick access times don't appear to be a priority for Seagate, whose 5,400 Momentus clocks in a whopping 3.6 milliseconds slower than the Scorpio and more than two milliseconds shy of its closest rival. No wonder Seagate doesn't publish seek times for its Momentus drives.
HD Tach's CPU utilization results are within the +/- 2% margin of error for this test.