HD Tune — Random access times
In addition to letting us test transfer rates, HD Tune can measure random access times. We've tested with four transfer sizes and presented all the results in a couple of line graphs. We've also busted out the 4KB and 1MB transfers sizes into bar graphs that should be easier to read without the presence of the mechanical drive.
The line graph mashes all the SSD results together, but it does an excellent job of illustrating the huge disparity in random access times between solid-state and mechanical storage. The differences are more than an order of magnitude, particularly with the smaller transfer sizes.
If we focus on the SSDs in the bar graphs, the Samsung 840 Pro Series is easier to spot. The drive sits in the middle of the pack in the 4KB test, where the new firmware produces slightly higher access times for both the 840 Pro and the 840 Series. Most of the SSDs, including the 840 variants, are locked in a virtual tie for the lead in the 1MB test. There and in the 1MB test, the new Samsung drives have an edge over the old 830 Series.
Virtually all of the SSDs are separated by a mere six microseconds in the 4KB random write speed test, so we'll move onto the 1MB results. There, the Samsung 840 Pro Series just trails the lead group of drives based on SandForce and LAMD controllers. The 840 Pro has quicker access times than the 830 Series, which in turn has a substantial advantage over the vanilla 840 Series. The new firmware has little impact on the performance of the new Samsung drives in these tests.