Seagate ST3320813AS manual Physical characteristics, Seek time, Typical seek times msec Read Write

2.4	Physical characteristics
Maximum height
	1500, 1000 and 640 GB models	26.1 mm (1.028 inches)
	320 and 160 GB models	20.17 mm (0.794 inches)
Maximum width		101.6 mm (4.000 +/- 0.010 inches)
Maximum length		146.99 mm (5.787 inches)
Typical weight
	1500 GB models	720 grams (1.587 lbs)
	1000 GB models	677 grams (1.493 lbs)
	640 GB models	543 grams (1.199 lbs)
	320 GB models	405 grams (0.893 lbs)
	160 GB models	390 grams (0.860 lbs)
Cache buffer
	ST31500341AS, ST31000333AS and ST3640323AS	32 Mbytes (32,768 kbytes)
	ST3640623AS and ST3320613AS	16 Mbytes (16,384 kbytes)
	ST3320813AS and ST3160813AS	8 Mbytes (8,192 kbytes)

2.5Seek time

Seek measurements are taken with nominal power at 25°C ambient temperature. All times are measured using drive diagnostics. The specifications in the table below are defined as follows:

•Track-to-track seek time is an average of all possible single-track seeks in both directions.

•Average seek time is a true statistical random average of at least 5,000 measurements of seeks between random tracks, less overhead.

Typical seek times (msec)	Read	Write
Track-to-track	<0.8	<1.0
Average* (1500, 1000 and 640 GB models)	<8.5	<10.0
Average** (320 and 160 GB models)	<11.0	<12.0
Average latency:	4.16

*Measured in performance mode. **Measured in quiet mode.

Note. These drives are designed to consistently meet the seek times represented in this manual. Physical seeks, regardless of mode (such as track-to-track and average), are expected to meet the noted values. However, due to the manner in which these drives are formatted, benchmark tests that include command overhead or measure logical seeks may produce results that vary from these specifications.

Barracuda 7200.11 Serial ATA Product Manual, Rev. C 11