Lab test: 8 ATA / S-ATA 7200 RPM hard drives (page 3: Recognizing a hard drive)

How to recognize the 8 MB of cache?

If all of these Serial ATA hard drives are equipped with 8 MB of cache, this is not necessarily the case with classic ATA hard drives equipped with 2 or 8MB. How do you know the cache size without using software? Simply by looking at the model number.

- Hitachi 7K250: 2 last figures of the number, 20 for 2 MB and 80 for 8 MB

- Maxtor DM+9 : 6th letter of the number : L for 2 MB, P for 8 MB

- Western Digital : 2 last letters of the hard drive name : BB for 2 MB, JB for 8 MB

- Seagate 7200.7 : 3 last three figures of the number :
40 GB : 2 MB only (ST340014A)
80 GB : 2 MB only (ST380011A)
120 GB : 2 MB (ST3120022A) or 8 MB (ST3120026A)
160 GB : 2 MB (ST3160021A) or 8 MB (ST3120023A)
200 GB : 8 MB only (ST3200822A)

How to recognize a hard drive with 80 GB per platter

This is more difficult. With Hitachi and Seagate it’s easy, the 7K250 and 7200.7 have inevitably 80 GB per platter (except for the Seagate 200 GB with two 100 GB platters). The situation with Maxtor and Western is different. The DiamondMax Plus 9 usually had 60 GB platters, and the transition to 80 GB platters was made progressively. Maxtor hasn’t officially informed us of the way to recognize these hard drives even if it was possible to find both on the market. Now, the transition is over and the problem no longer exists.

For Western Digital it’s even more complicated. The manufacturer has never released a line of hard drives based on platter size. Since its release, the 8 MB cache 120 GB ATA is named WD1200JB. This WD1200JB denomination, however, is also used for hard drives with three 40 GB platters, two 60 GB platters or two 80 GB platters (with one face disabled for one of them). It’s not possible for the final user to recognize any of them.

Western initially told us that all hard drives manufactured since the second quarter had 80 GB platters, but we noticed this wasn’t accurate. We found a WD1200JB manufactured in August and its performance showed it was equipped with 40 GB platters!

The hard drives tested here all have 80 GB platters and were manufactured in September. It would be in Western Digital’s interest to modify the name of their products according to platter capacity but as they’ve used this configuration for some time now this option is less likely.