Western Digital’s Raptor WD740GD SATA hard drive

To give its 10K-RPM Serial ATA drives more widespread appeal, Western Digital upped the Raptor’s capacity to 74GB for the WD740GD model, but didn’t stop there. The new Raptor’s internals have also been tweaked to give the drive faster seek times and transfer rates, lower noise levels, and support for command queuing. How does this latest Raptor fare against its Serial ATA and SCSI-based competition? Let’s find out.

The drive
Before we look at the performance of this latest Raptor, let’s see how the WD740GD’s specs compares with those of its predecessor.

In many ways, the WD740GD is identical to the WD360GD. Both drives feature 10,000RPM spindle speeds, 8MB of cache, 37GB platters, and five-year warranties. However, the WD740GD has a quicker read seek time and faster average sustained transfer rate than its little brother. The WD740GD also uses fluid dynamic bearings, which should make it quieter than the WD360GD.

Despite its somewhat menacing specs, the WD740GD’s appearance doesn’t exactly exude speed. Then again, hard drives tend to look alike.

The easiest way to distinguish the WD740GD from a “parallel” ATA hard drive is to look at its interface ports. Though the drive features a standard four-pin Molex connector, it’s also packing Serial ATA data and power plugs. You can use either of the drive’s power plugs, though I prefer the four-pin Molex plug since it fits a little more snugly than the Serial ATA power connector.

Although the Serial ATA spec does away with master/slave relationships, the WD740GD still has a jumper block. Rather than controlling the drive’s master or slave status, the jumper block is used to enable a special power-saving mode that boots the drive in a standby state. Western Digital recommends the drive’s standard power mode for most users, though.

Flipping over the WD740GD reveals its Serial ATA interface, Marvell’s 88i8030C bridge chip. Currently, Seagate Barracudas are the only drives to offer a native Serial ATA interface, but since the WD360GD easily outperforms even the fastest Barracuda, bridging isn’t anything to worry about.

Thus far, everything about the WD740GD suggests that it will offer better performance than its predecessor right out of the box. As if that weren’t enough, the WD740GD should also get a performance boost when Serial ATA controllers support the drive’s Tagged Command Queuing (TCQ) feature. The original Raptor lacks TCQ support, which allows the WD740GD to re-order outstanding requests with efficiency in mind. Unfortunately, Serial ATA controller cards with command queuing support have yet to hit the market.

The WD740GD’s TCQ support should help the drive compete with SCSI gear, which already supports command queuing. The performance benefits of TCQ should be especially apparent in multi-user benchmarks like IOMeter, where the original Raptor doesn’t scale as well under increasing loads as 10K-RPM SCSI drives. We’ll be sure to revisit the WD740GD when Serial ATA controllers that support command queuing become available.

A note on the testing
Product reps have a habit of freaking out whenever we throw an orange or banana into an apples-to-apples comparison, but that’s not going to stop us from testing the WD740GD against not only the WD360GD, but also a pair of 7,200RPM drives, a couple of 10K SCSI disks, and even a two-drive “parallel” ATA RAID 0 array.

With a 2,800RPM spindle speed advantage, the Raptors are easy favorites over the other Serial ATA disks. However, it’s important to note that the Raptors are only available in 37 and 74GB capacities, and both models are quite expensive compared to Serial ATA offerings from Maxtor and Seagate.

Since the Raptors are built for high-end workstations and servers, comparing their performance to 10K RPM SCSI drives is also appropriate. However, there are a few things to keep in mind when we throw SCSI into the mix. First, our Adaptec 29320-R SCSI controller supports command queuing, which should give our SCSI drives an edge over the WD740GD, at least until the Raptor’s TCQ gets host controller support. Also, it’s important to note that Serial ATA drives support a WRITE_THROUGH flag that demands that data is written directly to the disk rather than to the drive’s cache. For reasons I outline in this section of our 10K-RPM hard drive comparison, I haven’t disabled WRITE_THROUGH for our SCSI disks.

Our testing methods
All tests were run three times, and their results were averaged, using the following test system.

The Serial ATA, SCSI, and RAID cards were each used in the motherboard’s PCI-X slot and had the entire PCI-X bus to themselves throughout testing.

A special thanks goes out to the Computer Repair Shop and KickAss Gear for kicking in the Western Digital Raptor WD360GD and WD 740GD we used for testing

We used the following versions of our test applications:

• ZD Media Business Winstone 2001 1.0.3
• ZD Media Content Creation Winstone 2002 1.0.1
• ZD Media WinBench 99 Version 2
• LAME 3.89
• Xmpeg 4.5 with DivX Video 5.02
• ATTO ExpressPCI Utilities v163
• Intel IOMeter v2003.02.15
• Xbit Labs File Copy Test v0.3
• TCD Labs HD Tach v2.61

The test systems’ Windows desktop was set at 1024×768 in 32-bit color at a 75Hz screen refresh rate. Vertical refresh sync (vsync) was disabled for all tests.

All the tests and methods we employed are publicly available and reproducible. If you have questions about our methods, hit our forums to talk with us about them.

Winbench

The WD740GD leads the way in Winbench 99’s Diskmark tests and offers a healthy performance boost over the WD360GD.

The WD740GD also leads the single-drive pack in Winbench’s transfer rate tests, though the Raptor falls to our two-drive RAID 0 array at the beginning of the disk. This time around, the WD740GD is much faster than the original Raptor.

It doesn’t quite manage a win in Winbench’s access time test, bit the WD740GD is only 0.1 milliseconds slower than Maxtor’s Atlas IV. More importantly, Western Digital has improved the new Raptor’s access times over its predecessor.

HD Tach

The WD740GD continues to put on an impressive show in HD Tach’s read speed tests, where the drive’s average and minimum transfer rates lead all competitors. Maxtor’s Atlas IV and Western Digital’s original Raptor do spike to higher maximum read speeds, though.

Our 7,200RPM drives get a little revenge in HD Tach’s write speed tests, but the WD740GD still turns in the best minimum write speed and the second fastest average write speed.

In HD Tach’s random access time test, the WD740GD leads even the 10K-RPM SCSI drives, though only by fractions of a millisecond. Again, note how Western Digital has improved the WD740GD’s access time, and also note how much faster both Raptors are than the 7,200-RPM Serial ATA drives.

None of our Serial ATA drives can keep up with Ultra 320 SCSI when it comes to burst speeds, but that’s to be expected. The Serial ATA spec tops out at 150MB/sec, which isn’t fast enough to catch our 10K RPM SCSI drives in this test. Still, the WD740GD leads all our Serial ATA drives and is quite a bit faster than the WD360GD.

The WD740GD’s CPU utilization is a little higher than the competition in HD Tach, but not by enough of a margin to cause concern.

HD Tach – continued
Because we can, let’s check out some nifty graphs of HD Tach’s transfer rate tests across the entire length of our disks.

I’d normally be a little worried about the fact that the WD740GD’s read transfer rate dips more frequently than the WD360GD, but since the former is much faster overall, I’m not complaining. For comparison, the transfer rate graphs for the other drives are below:

ATTO

Both Raptors are closely matched in ATTO’s 1MB read speed test. I suspect our 3ware RAID card’s on-board cache is responsible for the RAID 0 array’s exceptional performance here.

Although the WD740GD has been largely faster than its predecessor thus far, the latest Raptor is well off the pace in ATTO’s 1MB write speed tests. Don’t panic, though. Redemption is just around the corner.

In ATTO’s 32MB read speed test, the WD740GD bounces back with an exceptionally fast performance that’s good enough to best all but our RAID 0 array.

The Raptor WD740GD leads all competitors in ATTO’s 32MB write speed test, suggesting that the drive may be optimized for longer transfer lengths than the WD360GD.

Business and Content Creation Winstone

The WD740GD comes out on top in the Business Winstone and also fares well in the Content Creation test.

Media encoding

All the drives offer roughly the same performance in our encoding tests. I suspect that our test system’s Pentium 4 2.26GHz processor is the bottleneck here.

File Copy Test

The Western Digital WD740GD offers the quickest file creation times across all but one of File Copy Test’s patterns. When compared with its predecessor, the WD740GD is faster across the board—often by significant margins.

The results of File Copy Test’s read time tests are more mixed. In this test, the WD740GD’s performance is excellent with some test patterns, but only average with others.

The WD740GD fares a little better in File Copy Test’s copy time tests, but the Atlas IV owns this one.

IOMeter – Transaction rate

Although both Raptors offer far better performance than our other Serial ATA drives in IOMeter’s transaction rate tests, they can’t hold a candle to SCSI performance as loads ramp up. The WD740GD’s TCQ support could help here once the drive is paired with a controller card that supports command queuing.

IOMeter – MBps

IOMeter’s MBps scores are a function of our transaction rate results, so the WD740GD’s relative position is unchanged.

IOMeter – Response time

The WD740GD offers the fastest response time of any Serial ATA drive in IOMeter, but again, the SCSI drives scale much better as load increases.

IOMeter – CPU utilization

On average, the WD740GD’s CPU utilization is somewhere between the 7,200-RPM Serial ATA drives and the SCSI disks. Either way, total CPU utilization is low enough not to be a concern for any of the drives.

Boot times

The WD740GD has a much faster boot time than any of our other drives.

Noise levels
Noise levels were measured using an Extech 407727 Digital Sound Level Meter placed one inch from the drive. The test system’s CPU fan was disabled to isolate noise created by the drives.

The WD740GD’s fluid dynamic bearings make it one of the quietest drives at idle. However, the new Raptor gets quite a bit louder under during seeks.

Heat levels
Using my incredibly scientific “how much does it burn my hand” test, I found the WD740GD to be no hotter than the WD360GD or either of our 10K RPM SCSI drives. After a few hours looping IOMeter, you could probably cook an egg on any of the drives we tested.

Conclusions
The WD740GD is by far the fastest Serial ATA hard drive available, but performance doesn’t come cheap. With a street price of $230, the latest Raptor costs twice as much as its 37GB predecessor, and much more than Maxtor and Seagate’s Serial ATA offerings. Still, the Raptor WD740GD’s price tag is actually quite reasonable when compared with 10K-RPM SCSI gear, so it’s hard to call the this drive overpriced. Also, remember, the Raptor packs a five-year warranty.

If you’re looking for the fastest performance for single-user applications, it doesn’t get much better than the WD740GD. The original Raptor was already an impressive performer, and its successor’s improved performance and larger capacity take the goodness to the next level.

Unfortunately, as great as the WD740GD is in single-user applications, the drive doesn’t scale nearly as well as 10K RPM SCSI disks under multi-user loads. The WD740GD’s tagged command queuing support should help boost multi-user performance, but this capability won’t be tapped until controller cards arrive with TCQ support.