HD Tach: SSD Performance

EDITOR'S NOTE: HD Tach offers very basic bandwidth speed results at a single queue depth. HD Tach uses buffered spot samples, therefore NAND wear conditions on segments tested may impact performance results.

Okay, before we being this section, I must give the legal disclaimer: Simpli Software has not designed their HD Tach software to be used for SSD technology. Just look at the name; HD stands for Hard Drive. Cross your fingers and hope for SSD Tach sometime soon, but in the mean time we use what we've got.

In our last section, we witnessed HD Tach report a burst speed advantage to the Intel ICH10 chip, while the write bandwidth heavily favored the JMicron chip. Read performance was virtually (and sometimes literally) identical. In this section, it's time to test SSD products, and see of HD Tach offers consistent results.

For anyone who didn't fully understand how data is written to a Solid State Drive, perhaps one of my famous analogies will help explain. Think of an ice cube tray. If the tray was a HDD, water (data) would fill the tray from beginning to end. But when the tray is a SSD product, water goes to the least fills areas first so that the tray receives a level amount all-around. It is this wear-level feature that causes so many problems for benchmark software, primarily because most tools were designed to spot-test sectors of a hard disk, and with a SSD these spots could be anywhere depending on the amount of wear to the modules.

Beginning with the Silicon Power 32GB SLC SATA-II SSD, we see that burst speed still favors the Intel ICH10 controller, even though SSD burst speed is a virtually useless figure because of internal cache mechanisms. Sequential read speeds using the JMB322 are 97.1 MBps, while the ICH10 produces 103.0 and produces a nearly 10% improvement. This shatters our previous findings which demonstrated comparable read-from results between chips. The next major difference is the write-to performance, which still favors the JMicron controller with 76.6 MBps over Intel's 66.8. That's expected, but look at the read pattern: JMicron has a somewhat stead waveform while the Intel controller makes me a little concerned.

Moving on to our recent 2008 Editors Choice Award winner, the G.Skill FM-25S2S-64GB MLC SSD, we realize that anything can happen with HD Tach. Sure, the burst speeds (which should really be ignored for SSD testing) are in very-slight favor to the Intel ICH10 chip, which has been consistent throughout our testing, but the rest is a little different. The G.Skill SSD performs read-from bandwidth at 123.2 MBps on the JMicron, while the write-to performance is only 113.2 for the ICH10 chip. Going from identical performance between HDD tests to almost 10% difference swaying back-and-forth between controllers is not something a tester wants to see.

At this point, my technically-minded brain wonders if the internal controllers present inside SSD products are coded specifically for the different SATA controllers, or if HD Tach has become suspect. All good questions, and so far there are no good answers.

By this point in my Solid State Drive Benchmark Performance Testing article, you might have noticed that we're using 6GB of triple-channel DDR3 on a 32-bit Windows XP platform. Benchmark Reviews is well aware of the memory mapping limitations of 32-bit software, so please don't send us mail to remind our staff. But does it matter? Does it make a difference to performance or test results? Benchmark Reviews has taken the extra steps necessary to answer this question, and perhaps save the good name of HD Tach, all in our next section.

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