Note: for an in depth look at how Serial ATA really works, check out our companion story explaining the details.
Seagate sent us their latest Serial ATA drive, the ST3120023AS. The drive mechanism is identical to the ST3120023A parallel ATA drive we recently tested — right down to the 8MB buffer. So we thought it would be eminently fair to compare the performance of the two drives.
We also tossed in benchmark results from the other 60GB/per platter drives we reviewed recently for good measure.
We were able to use the same testbed as we did with the original large hard drive roundup, since the Intel D845PEBT2 motherboard has a Silicon Image 3112 PCI S-ATA controller soldered to the board, and support in the BIOS for booting from a Serial ATA drive.
Here are the testbed specifications:
Building in a Serial
ATA Drive”> Of course, before you can benchmark a drive, you actually have to install it and get it running. That proved to be more of a chore than we expected.
Using a Serial ATA drive in your system can be somewhat problematic. If you want to simply add an S-ATA drive as a secondary or tertiary drive, its fairly simple to bring up — attach the drive, boot up, install the driver into the OS and off you go.
Oops, not quite. There is the issue of the power connector.
If you examine the picture closely, youll note that the power connector isnt the familiar 4-pin, Molex 12 volt connector weve all wrestled with. Instead, its an edge connector, that looks a bit like a wider version of the S-ATA data connector.
While many motherboards now ship with motherboard down Serial ATA support, and even supply you with data cables, almost none of them supply you with power adapter cables. No off-the-shelf power supply currently has connectors for S-ATA power plugs either. We did find two Gigabyte motherboards with adapters for using the drive external to the PC, but this is somewhat limiting.
What you need is a Molex 12V to Serial ATA power converter cable.
These are not widely available in your local clone shop yet, though now that S-ATA drives are shipping, you should be able to find them soon. However, SIIG, who manufactures a line of S-ATA PCI adapter cards, kindly supplied us with several. The SIIG S-ATA host adapter kit ships with one inside the box.
Once you get power and data to the hard drive, the next step is to connect it to the motherboard. The edge connector is keyed, so you cant install it the wrong way. If you examine the motherboard connector, youll see the L-shaped key on one side of the connector.
Plugging the connector into the motherboard is literally a snap — certainly easier than trying to line up and push down that pesky parallel ATA cable. Once in, the connector and cable take up very little room.
When installing Windows XP, we had to do a clean install — simply copying over a partition wouldnt work, due to the dreaded “Stop 0x0000007” error. This particular error usually indicates that the mass storage device isnt recognized properly by Windows. So you have to install from scratch, making sure you have a floppy with the proper Serial ATA host adapter drivers handy. Its much like installing a SCSI host adapter.
As Serial ATA becomes more commonplace, its likely to be built into the operating system. There are currently three major suppliers of S-ATA chipsets: Silicon Image, Promise and Marvell (though the Marvell chip is really a parallel-to-SATA bridge chip). Once the standard is built into the core logic, an update to the OS will likely be needed.
Serial ATA support for Linux is well under way. Last August, driver source was released for the SiL 3112. Theres no word yet on Linux support for the Promise S-ATA controller. You can check out support for the SiL chip at the Linux IDE project.
ZIFFPAGE TITLEBenchmark Results
We ran the same set of benchmarks as we ran with our recent large drive roundup. This means that we can compare the performance directly with some the most recent parallel ATA drives.
We put the following products under test:
- Winbench 99 version 2.0 Disk Tests. We ran the two Winmark tests (Business Disk Winmark and High End Disk Winmark. We also ran the CPU utilization, access time and transfer rate inspection tests. The transfer rate was normalized to 8MB (8000KB), as suggested by the designers of the Winbench 99 disk test — that is, the transfer rates for the applications playback tests were set to 8000 kilobytes per second.
- Multimedia Content Creation Winstone 2003, to see how the drives performed under a set of real-world applications, executing scripts that represent real user workloads.
- Business Winstone 2002, to test performance with a standard suite of desktop business applications.
Winbench 99 2.0 Business Disk Winmark Test Results & CPU Utilization
The result is pretty startling — the Seagate S-ATA drive outpaced all the others, by a wide margin. We repeated this test three times to be sure, and obtained essentially the same result each time. One clue to this amazing result may be found in the CPU utilization test.
Note the substantially lower CPU utilization. Its possible that the Silicon Image S-ATA controller simply has low CPU overhead relative to the embedded parallel ATA controller in Intels ICH4 I/O controller hub. Since Winbench 99 is a low-level that tests read performance above write performance, its likely that the low CPU utilization, plus some firmware optimizations, may have resulted in the higher Business Winmark Score.
High End Disk Winmark
As we can see, the S-ATA drives performance in the high end Winbench tests were pretty much in line with the performance of its parallel ATA cousin. In fact, the S-ATA Barracuda performed somewhat more slowly in most of the individual high-end tests, as we can see from the Microsoft C++ 5.0 compilation test.
However, the Microstation SE test gets a big boost from the S-ATA drive, relative to its parallel cousin:
Disk Access Time and
Transfer Rate Tests”> We complete the suite of low-level tests by looking at the results from Winbench 99s low level inspection tests.
The access time is in line with the parallel ATA drive, as it should be.
If we look at the transfer rate test at the beginning (outer tracks) of the disk, we can see higher transfer rates relative to the Barracuda V ATA drive, though theyre still not quite as strong as the competitors ATA drivers. Still, it lends credence to the belief that the firmware on the S-ATA drive has been tweaked, and to the possibility that the SiL 3112 controller is more efficient than Intels ICH4 parallel ATA controller.
The inner track transfer rate is more similar to the result for the parallel ATA drive, however.
Business and Content Creation
Winstone Results”> Now that weve seen the results using low-level disk tests, lets see what applications-level benchmarks reveal.
Interestingly, the results dont differ greatly from the parallel ATA results. However, note that the Business Winstone test results for the Serial ATA drive are a bit better than the parallel drive, while the MCCWS tests are slightly poorer. Despite the differences in applications, the nature of the differences are similar. The Winstone tests use much more recent versions of applications, and different apps to boot than those used to record the Winbench disk playback tests. But it seems that the Seagate S-ATA drive, when attached to the SiL controller, handles business apps better than the Barracuda ATA V.
Analysis and Conclusion
Serial ATA is here, finally. It probably wont make much of a dent in parallel ATA drives until the standard is integrated into the core logic. But since many new motherboards ship with S-ATA connectors, its certainly a viable option for secondary or tertiary storage. Most of these boards also have support for Serial ATA RAID as well, though the PCI bus may be a bottleneck in these cases.
Overall, we were pleasantly surprised with the performance of the Seagate drive. The benchmarks were, in general, as good or better than those of the parallel ATA version of the same drive. We suspect that performance in general should be pretty good for single drives. Note that youre not paying any premium, either, as the ST3120023AS is priced roughly the same as the parallel ATA ST3120023A.
The real bummer is that you wont be able to have an all S-ATA system even after support for Serial ATA arrives in the core logic. Until the optical drive manufacturers also get on board, well still have to live with those clunky parallel ATA cables. Also, large IT organizations will likely make the transition more slowly, due to their current infrastructure of parallel ATA systems.
But within a few months, there should be no reason to opt for parallel ATA hard drives for new systems for individual users. New motherboard chipsets arriving before midyear will have Serial ATA in the core logic, north of the PCI bus. Performance should be just a bit better, if only because the PCI overhead will be eliminated. Note, however, that its not known if any chipset maker will put S-ATA RAID in the chipset — now that would be fast and convenient.