Please help two drives co-exist

May 20, 2008 3:24 AM

SATA I or II? Hopefully very simple question about hard drives

I'm looking to buy a new internal hard drive for my ageing Dell. Thing is, I'm not sure about compatability. The original drive is described as '250 GB 1st SATA' on the Dell spec sheet. My question is, would this have been Serial ATA-300 or Serial ATA-150? What's the difference? All the drives I'm looking at seem to be ATA-300. Can this co-exist with the original drive? The computer was bought in February 2004, if that helps.

posted by jonathanbell to computers & internet (6 comments total)

The drives can co-exist with each other without any problems. You might have a problem with the motherboard not supporting SATA II disks though. A few SATA II drives I've bought have had a configurable jumper which allow it to run in SATA I/II mode depending on the presence of the jumper.

Can you reply back with the exact make/model of your motherboard or your Dell PC?
posted by cyanide at 4:04 AM on May 20

SATA II drive electronics should automatically downgrade to SATA I controllers without difficulty. The difference in the two specs is the theoretical data transfer rate; for SATA i, it's 150 MB/sec, for SATA II, it's 300 MB/sec. In practice, you never see anywhere near these rates as sustained transfer rates, for a number of practical reasons. Many benchmarks show 6 to 8% improvements in transfer rates for SATA II drives working with SATA II controllers.

But what matters to you is simply that SATA II drives will interoperate smoothly with the SATA I controller you probably have on your motherboard, and they should. Buy SATA II drives for future compatibility in newer computers, or spend a little less on older SATA I designs.
posted by paulsc at 4:07 AM on May 20

Thanks for these replies - very helpful. The motherboard isn't entirely clear from the spec sheet (the computer isn't in front of me right now), but it was a 'Dimension 8300 P4 with HT Technology 3.0Ghz 800FSB and 1MB cache'.
posted by jonathanbell at 4:12 AM on May 20

Well the other key difference is the power supply to the drive. SATA1 uses a molex whereas the SATA2 uses one of these puppies. So, if you do get a SATA2 drive, you'll need a molex to SATA2 adapter.
posted by squeak at 8:27 AM on May 20

That power supply connector change isn't a stupidly gratuitous as it looks, by the way; the SATA2 connectors are designed to allow hot swapping. Unplugging a Molex power connector while the drive is on risks damage to the electronics, because the Molex pins are not designed to disconnect in any defined order.
posted by flabdablet at 9:20 AM on May 20

Thanks everyone. I'll take the plunge with a SATA2 drive and see if I can figure it out, Molex and all.
posted by jonathanbell at 1:42 PM on May 20