Thursday, June 22, 2006

My New PC: The Hard Disk

The hard drive was a pretty easy choice for me.

A quick survey of high end gamer machines shows that they are typical going with several drives, arranged in RAID arrays. While I see the performance benefits of RAID, I'm not interested in the complexity or added expense of a RAID.

SATA 3.0Gb is a given in a new machine. so, my viable choices are:
  1. Standard SATA Drive
  2. A pair of WD Raptor 150s
  3. SATA with Perpendicular recording

The popular configuration in the $4000+ "killer rigs" is a pair of Raptors backed by a large SATA drive. That's great if you have $800-1000 in your pc budget for the hard drives alone. Its not realistic in my budget, and it is definitely not a good value for a normal system.

The advantage of the Raptors is that they spin at 10,000 RPM instead of the norm of 7,200RPM for standard desktop drives. That means the mechanical parts are all operating 30% faster. It DOES NOT mean that you will see a 30% increase in hard drive performance, because data cacheing strategies come into play. A 10K drive is 30% faster every time the data actually has to be read from the platter, but the net effect is considerably less than 30% improvement in throughput for normal activity.

The SATA Perpendicular drives store the data in a denser format, allowing more bytes to be packed into a given area on the platter. The ones that are currently available all spin at 7,200 RPMS (or less for notebook drives). Since the storage density is roughly 30% higher than on a non-Perpendicular drive, the transfer rate for information is roughly 30% faster from the platter. The spin rate in larger part determines how long it takes for the drive head to move to the data, so it will be slower at finding data than a Raptor but roughly on par with the Raptor at reading or writing the data. Again, the caching strategies come into play, but it is safe to say that a perpindicular drive should be on average a bit slower than a Raptor, and a bit faster than a standard SATA drive.

Now that this background research is out of the way, what about price. And how much data? I only plan on acquiring 1 drive for now, and my data needs are not huge. So, I've decided to shoot for one drive in the 250-400 GB range. That will meet all of my needs for now and for the next year, and leave plenty of room in the SONATA II's 9 drive bays for future expansion. It will, also minimize the load I'll be placing on the 450W power supply and reduce the head in the case by a bit.

The RAPTORS only come in 74 and 150GB sizes, so I would need 2 of those at a minimum. Note that two physicial drives will outperform 1 physical drive anyway, so that isn't the end of the world. Two Raptor 150s currently run $479 (after a $40 rebate) at NewEgg.

The SATA 300 Perpendicular drives are just coming to market, so the only one in my preferred size range is the Seagate 320. This drive currently goes for $109.99 at NewEgg...

Well, given a budget for this PC, that makes the choice pretty clear. The Raptors might buy me a measurable performance differnce of 10%, but they would raise the price of the hard drive component by 450%. Not good value.

Choice made, Seagate 320 Perpendicular.


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