Pros: Cost per MByte, SATA II, NCQ, 16 MByte cache, overall performance, low noise
Cons: 7200 rpm, write performance near center, SATA power only
The bottom line: Innovative perpendicular recording aside, this drive is quiet and relatively fast for a very reasonable price.
Bigger is better, not only in cars but also and especially in computer storage. While big car have become questionable, storage needs in computers have grown more and more and really there is no real relationship between the two other than filling both of our cars recently for little less than this new hard drive costs. Drive less and get more "drive" -- storage that is.


IN A NUTSHELL

Seagate shows innovation and packs the latest generation of hard drives full with innovation. The improved reliability of perpendicular storage may not become visible for many home users (assuming you rarely ever have a drive go bad), but the collection of features is a good argument in favor of the 7200.10 series.

The Barracuda series finally turned into a serious challenger of WD's Raptor (10k) drive which holds raw speed record in the SATA arena but overall usage of the Barracuda 7200.10 is occasionally superior due to technologies like NCQ and 16 MB cache.

At less than $0.30 per GByte (current street price), the ST3320620AS is attractively priced despite the technological advances. In fact, this is one of the cheapest SATA II drives with 16 MByte cache. Yet it's also one of the quietest with very respectable performance.


PERFORMANCE

More than a year ago, Seagate's 7200.7 series was a mere patch of an ATA drive with SATA added on and NCQ introduced in the process. Performance was in line with expectations for a 7200 rpm drive and similar to my other Seagate drive, but slight improvements are also visible. Keep in mind that a benchmark is typically tougher than real life performance ...

I configured my drive with two partitions and therefore had to run the benchmark twice -- to be sure. As expected the difference between the inner partition (A) and the outer one is significant, with one little surprise ...

Sandra2005: A vs. B vs. 7200.7* vs. Raptor
Buffered Read [MB/s] =120 / 124 / 89 / 121
Sequential Read [MB/s] = 60 / 74 / 57 / 68
Random Read [MB/s] = 41 / 48 / 41 / 38
Buffered Write [MB/s] = 106 / 106 / 100 / 82
Sequential Write [MB/s] = 59 / 73 / 57 / 68
Random Write [MB/s] = 37 / 42 / 39 / 52
Avg Access Time [ms] = 8 / 7 / 7 / 12
Drive Index [MB/s] = 52 / 63 / 51 / 58

*... 80 GByte, 8 MByte Cache, 7200 rpm, SATA, NCQ
A ... 7200.10 inner partition (111 GB)
B ... 7200.10 outer partition (186 GB)

Interpretation: The surprise is perfect and the Barracuda takes the lead on the more dense outer partition and shows that density can beat spindle speed. (It's not exactly a direct comparison since the other drives were a single partition.) Anyway, the inner portion performed similar to the 7200.7 which is expected, but the outer partition shows the true advantage of the 7200.10, especially the sequential tests which both belonged to the 10k Raptor before. Higher density makes it possible, but surprisingly random write is still in the Raptor's favor. (Watch out though for the 150 GB version of the Raptor which packs more punch than the 74 GB.) The larger buffer signs responsible for the buffered read and write and the 7200.10 takes the lead even ahead of the Raptor in this regard. This is not completely surprising since in this test the mechanics are not the main driver, hence the similar performance between both partitions.

I repeated the test with the more descriptive HD Tach 3 to determine raw hardware speed depending on the position on the platter. This time the Raptor showed the higher base speed which is especially noticeable on the typically slower inside while the density of the 7200.10 wins on the outside. The higher average of the Raptor is mostly a result of the consistent performance of roughly 70 MB/s for an impressive 60% of the disk size. The 7200.10 maintains an average of 75 MB/s only for less than 20% of the total size.

HD Tach 3 (Sequential Read)
WD RAPTOR 74: 52 MB/s ... 73 MB/s (inside ... outside) - AVG 65 MB/s
Barracuda 7200.10: 40 MB/s ... 80 MB/s (inside ... outside) - AVG 63.5 MB/s


DETAILS

Identification: [***--] Seagate's numbering system is confusing to say the least, despite its seemingly simple design. Often referred to as 7200.xx where 7200 stands for the spindle speed and .xx for the generation. In this case ".10" stands for perpendicular recording. While that all may make sense, it's hardly the way to find it in a catalogue and the package will not call out the generation either. Here it's the much more cryptic ST3320620AS which is far less descriptive. The only easy to recognize parameters here is the "AS" that signifies the SATA bus. This is significant since leaving off the "S" describes the same model but for the ATA/100 bus -- two fundamentally different things. Apart from that, there is no easy way to tell how much cache is in a drive or whether it supports NCQ and so on. So make sure to check the whole number when ordering.

Reliability: [*****] Basically every recent hard drive on the market is S.M.A.R.T. compatible -- a drive condition monitoring feature provided by most BIOS in modern motherboards. Useful as it is, it often is required to enable it manually for an installed hard drive (in the BIOS). Once that's done, the system checks several crucial parameters during startup. The values are recorded and compared to the stored specs of this drive. Further, the trend is extrapolated to predict hardware failure -- or at least when one of those values reaches a critical number. This is mostly statistically derived, but worth the consideration to prevent data loss. Adaptive Fly Height offers consistent read/write performance from the beginning to end of your computing workloads. Clean Sweep automatically calibrates your drive each time you power up. Directed Offline Scan runs diagnostics when storage access is not required. Enhanced G-Force Protection defends against handling damage. Seagate even offers a 5-year warranty.

SATA II (300): [****-] The speed of traditional ATA bus is becoming more and more a potential bottleneck, but not for single hard drives and seldom for two drives either. This becomes clear when looking at the ST3320620A which is identical to this drive except for the ATA/100 interface. The true limitations come from RAID setups and recent speed improvements in hard drive technology. In fact, a RAID for data striping and redundancy (mirror) pretty much requires 4 drives to talk "simultaneously". Take the advertised 78 MByte/sec for the 7200.10 and it becomes clear why SATA II makes sense (in those extreme applications). Though the sum of 312 MB is rather theoretical and often divided into two streams anyway. For the normal user there is little difference between SATA (150 MB/sec) and SATA II (300 MB/sec). In fact, even the limits of ATA/100 are seldom the bottle neck in home applications. This drive is self-configuring depending on your controller's capabilities and works with both SATA generations. It can be forced to SATA 150 via jumper if you have to. (Default)

Perpendicular Storage: [*****] This is really the one feature that sets the 7200.10 series apart from the rest of the market. However, ther first drives in this technology were the Momentus 5400.3 for mobile computing. Perpendicular Recording increases data density and enables larger storage due to higher density. This is achieved by recording the magnetization of the disc stands on end, perpendicular to the plane of the disc. In traditional drives the oriention is along the disc's plane (longitudinal recording). The perpendicular orientation basically doubles the available recording recording density. Increase of density allows to compensate for "low" spindle speeds. Eventually, storage capacities with a typical 3.5-inch desktop drive is said to reach up to two terabytes of information with this new technology. The largest 7200.10 drive so far clocks in at an amazing 750 GByte! Seagate doesn't stop with 7200 rpm drives and currently introduced perpendicular technology into their Enterprise product line with the release of the Cheetah 15K.5 product series -- effectively doubling the storage capacity. However, that's currently reserved for SCSI and really pricey.

Noise: [*****] Seagate holds their SoftSonic motor responsible for the "whisper-quiet" operation. Indeed, the drive stays quiet even under heavy load and that may also partially due to the 7200 rpm -- at least when comapring it to the slightly more present WD Raptor, a 10,000 rpm drive. For both it's recommented to use rubber mounts when fastening it to the frame. Further, check that frame for loose components, as the remaining transmitted vibration may still cause a rattle here or there. The drive itself is extremely quiet -- which is generally true for most modern Seagate drives but even more so for this one.

7200 RPM: [***--] Sustained transfer speed (large files) heavily depends on two factors: data density and and the speed with which the data is presented to the head(s). For the latter, the spindle speed is one of the main factors and 7,200 rpm are a standard speed for mainstream desktop computers. It sure is not the lofty 10,000 rpm or 15,000 rpm that have become the reference in the SCSI world but it also is a good compromise between cost, speed and reliability. Not only is 7,200 relatively proven, it also poses less problems for proper head alignment and therefore less chance to destroy the drive. That higher speeds can be reliable too as many enterprise-grade drives have been shown before, but the low cost associated with 7,200 rpm mechanics will keep those drives around for a while.

NCQ: [*****] Native Data Queuing (NCQ) has become the norm in Seagate's SATA desktop drives. In conjunction with the large cache, the Barracuda 7200.10 series allows to streamline commands even better and fetch data in an optimized fashion relative to its position on the disk. The reading head travels less if data within the sequence is closer. The actual order of the data is restored upon transmitting it back to the CPU. The effect is naturally limited in less predicatble situations or simply too large chunks of instructions and data.

16 MB Cache: [****-] Since mechanical speed is limited, prefetched data can be stored in the relatively large 16 MB Cache and transfer rate is ultimately higher than the heads would allow. Depending on your application, this may be significant, but typically has no effect on operations like recording video due to the large files which virtually bypass the buffer.

© 2006, theuerkorn


LINKS

- Seagate Barracuda 7200.7 - 80GB hard drive
- Western Digital Raptor - 74 GByte hard drive
- Western Digital Raptor X - 150 GByte hard drive