Seagate ST3250620NS, ST3250820NS Recording and interface technology, Physical characteristics

2.4Recording and interface technology

	750GB	500GB	400GB	320GB	250GB
Interface	Serial ATA (SATA)
Recording method	Perpendicular
Recording density, KBPI (kbits/inch max)	926	813	781		813
Track density, KTPI (ktracks/inch avg)	145
Areal density (Gbits/inch2 avg)	128.2	114.4
Spindle speed (RPM) (± 0.2%)	7,200
Internal data transfer rate (Mbits/sec max)	1,030
Sustained data transfer rate (Mbytes/sec max)	78	72
I/O data-transfer rate (Mbytes/sec max)	300 (Ultra DMA mode 5)

2.5	Physical characteristics
Maximum height		26.1 mm (1.028 inches)
Maximum width		101.6 mm (4.000 +/- 0.010 inches)
Maximum length		146.99 mm (5.787 inches)
Max weight
	ST3750640NS and ST3750840NS	720 grams (1.59 lbs)
	ST3500630NS, ST3500830NS, ST3400620NS,	635 grams (1.4 lbs)
	ST3400820NS, ST3320620NS and ST3320820NS
	ST3250620NS and ST3250820NS	580 grams (1.28 lbs)
Cache buffer
	ST3750640NS	16 Mbytes (16,384 kbytes)
	ST3500630NS
	ST3400620NS
	ST3320620NS
	ST3250620NS
	ST3750840NS	8 Mbytes (8,192 kbytes)
	ST3500830NS
	ST3400820NS
	ST3320820NS
	ST3250820NS

Barracuda ES Serial ATA Product Manual, Rev. D 15