We compared the Hitachi T7K250 250GB, Samsung SpinPoint SP2504C 250GB, Seagate 7200.10 300GB, and Western Digital WD3200SD 320GB for capacity, performance, warranty, and price, to determine class leadership and overall value.

A scale of 10 is used for each category, beginning with Capacity. Because the WD3200SD leads this comparison at 320GB, we gave it a 10 as offering the most capacity in this price range. We'll also base other drive scores on a percentage of this capacity. Accordingly, 300GB is 94 percent of 320Gb, giving the 7200.10 a 9.4 out of 10 points. 250GB is 78 percent of 320GB, giving the T7K250 and SP2504C 7.8 out of 10 points.

Because 3Gb/s is still an unrealistic goal for transfers from medium, we choose 150MB/s from the older SATA 150 standard as a basis of comparison. Since 150 divided by 15 equals 10, transfer scores from all benchmarks are averaged and divided by 15 to put them on a scale of 10. This method gives the T7K250 7.2 out of 10, the SP2504C 7.0 out of 10, the 7200.10 7.90 out of 10, and the WD3200SD 4.9 out of 10.

We chose 20ns as an arbitrary "worst expected seek time" and 10ns as an arbitrary "target seek time." We then averaged the seek times for each drive from all benchmarks. Subtracting actual seek times from 20 provides the highest score for the quickest drive, as it would give 10 points for 10ns and 0 points for 20ns. The resulting scores are 9.7 out of 10 for the T7K250, 9.2 out of 10 for the SP2504C, 7.6 out of 10 for the 7200.10, and 9.5 out of 10 for the WD3200SD.

Averaging the transfer and seek scores for each drive provides the combined performance rating.

Warranty points are easiest to score because multiplying the top warranty period of five years by two gives it 10 out of 10 points. Multiplying a three-year warranty by two gives it 6 out of 10 points.

Price scores reflect the inverse relationship between cost and value. We used search engines to find the average price at the five most inexpensive online retailers for bare drives. At the time of this article, we found approximate average prices of $87 for the T7K250, $88 for the SP2504C, and $115 for the WD3200SD. Available within a week, we estimate the 7200.10 300GB/8MB drive will find an average discount-vendor price of $115, based on the 7200.10 320GB/16MB's average price of $122.

Assuming a "target price" of $80 and a "price ceiling" of $160, we began with 10 points and subtracted one point for every $8 over $80.

Final value calculations average those of each category: Capacity, Performance, Warranty, and Price.

Looking at the numbers, the first surprise is Seagate's high data rate playing second fiddle to Hitachi's much faster write access, though a superior warranty puts the 7200.10 at the top for overall value.

Another surprise for us is that Western Digital's older SATA150 drive was able to tie the better-performing 7200.10 and beat two less-expensive models in ultimate value, even after losing in both comparative performance and price. Credit Western Digital's enhanced warranty on Enterprise products, along with its class-leading capacity!