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Seagate Cheetah X-15 Hard Drive

Seagate's next-generation 15,000-rpm X15 Cheetah hard drive is a true audio/video drive that is capable of the most demanding applications.

Seagate’s next-generation 15,000-rpm X15 Cheetah hard drive is a true audio/video drive that is capable of the most demanding applications.
Product PointsApplications: Digital audio/video production

Key Features: 15,000 rpm; Ultra160 SCSI interface; 160 MBps burst rate; 3.9 microsecond access time

Price: $500

Contact: Seagate at 1-800-SEAGATE;


+ Fast

+ Relatively inexpensive

+ Quiet

+ Runs cool


– None

The Score: Moving up to the Seagate X15 is essential in this brave new high-bandwidth world.

The X15 uses the latest Ultra 160 LVD 68-pin SCSI interface. Data transfer burst rates on the X15 hit as high as 160 (!) MBps with sustained rates of 48.9 MBps and an average seek-time of 3.9 milliseconds. The drive is actually quieter and runs cooler than the 10,000 rpm SCSI Cheetah drives it replaces.

Seagate carried out a massive redesign to achieve all this. To get the drive faster, cooler and quieter meant dividing the storage into many smaller platters. The platters are the discs the magnetic information is written to and read from. Shrinking them makes it easier to spin them faster. The X15 has five discs and 10 heads.

Other design improvements make the drive more resistant to vibration while operating. When multiple drives are installed (for example, in a server environment), the accumulated vibration is enough to cause data errors – the X15 withstands up to 0.5 Gs.

In use

The first step was installing Adaptec’s 19160 Ultra 160 SCSI controller card into a PCI slot. The Adaptec card effectively integrates all the slower SCSI standards – Ultra, Ultra Wide and Ultra2 – permitting legacy devices without defaulting to the lowest speed.

The BIOS on the card recognized the X15 drive automatically. Partitioning and formatting the drive’s 18.35 GBs to install Windows NT was simple. Booting up, a perceptible change in how fast programs and files popped up on the screen, compared to my Ultra2 SCSI drive, was immediately obvious. Cutting the hard-drive access times in half gave a systems boost similar to what I saw when I moved up one generation in CPU power.

Inside the case, noise levels were less than the fans spinning to keep things cool. The relatively low heat levels generated were also incredible. I had expected this thing to get hot enough to fry eggs on, but the standard air-venting-through-the-case/power supply is enough to keep this cool. For good measure, I placed a CPU fan from an old computer on the X15. That keeps it downright chilly. I fully expect it to live up to the record-setting 1.2-million hour mean time between failures (MTBF) rating. This is likely to outlast most every other component in the system.

What does this do for audio production? Doing the math on hard-drive access is easy; a stereo track of 16-bit 44.1 audio eats up about 0.17 MBps in data rate bandwidth. Multiply that times 24 tracks and you’re up around 4 MBps. Max out Cool Edit Pro’s 64-track capability and you’re still under 11 MBps. Pumping up to 24/96 audio multiplies the data-rate demands by a factor of almost four.

Testing the X15 with IQS’ 32-Bit Hard Disk Speed Test showed that this does indeed set new records. The utility is designed to check if a hard drive is fast enough to work with the SAW multitracker. My Ultra2 SCSI 10,000-rpm Cheetah 9LP ST39102LW scored 15.7 MBps with a write speed of 9.3 MBps – a considerable achievement two years ago. The X15 is in a different league.

The read test on a 30 MB audio file was a whopping 33.9 MBps – better than double what the Ultra2 drive managed. The read speed was even more impressive – 35.9 MBps. Admittedly, this is not going to give enough bandwidth for a full 64 tracks of 24/96 audio. If that’s your game, shell out another $600 and add a second X15 to double these figures. Besides, you’ll need more than 18 MBs to handle such a monstrous project.

All this hard-drive power can reveal shortcomings elsewhere in a digital audio workstation – usually CPU speed and RAM. Moving all that data in and out of the drive is one thing – applying loads of processing to all those bits of audio takes a lot of heavy lifting and can easily choke a system. As they say in the computer business, you don’t remove bottlenecks – you just push them back.

The X15 is not the cure-all that will magically transform any computer into a state-of-the-art workstation – that’s why they call them computer systems. The overall performance is a product of the relation of the elements. It’s like getting a new low-noise microphone and discovering the mixing board noise that was hidden under the old mic.


For those working with less than a gargantuan number of tracks, the X15 seems like overkill. Other than enjoying a faster system, a few advantages are obvious. I was able to burn 12X CD-Rs without worrying about a buffer underrun spoiling the disk. In fact, the drive is fast enough that I was able to run other programs – actually multitask – while cooking a CD-R. Previously everything else had to come to a crashing halt to make a CD-R. Not so anymore.

The X15 also opens other possibilities as standalone audio production be-comes wedded to video work. Say a client wants to get better sound to go with footage of a club performance captured with a DV recorder. If 24/96 audio is a bandwidth hog, DV data is a whole drift of hogs. Uncompressed DV is 20 times the size of 16/44.1 audio – more than 200 MB a minute. So for those getting ready for the demand for true A/V production, the X15 is essential.