Hard Drive Limited to 1.5 GB/sec?
January 14, 2009 11:59 AM   Subscribe

So I'm installing a new Seagate 500GB SATA HDD in my PC, when I notice, for the first time somehow, a jumper that limits the drive to 1.5 GB/s. What's that all about?

Limits to 1.5GB/s as opposed to, I'm assuming, the 3.0GB/s advertised with most modern SATA drives, including the one I bought. Upon further investigation, both my other drives are running with the jumper on, limiting my transfer speeds.

I understand that 3.0 GB/s isn't even considered possible really, but why 1.5GB/s? And do I want it limited for just your standard, non-RAID gaming configuration? What does it all mean?
posted by Avenger50 to Computers & Internet (6 answers total)
Best answer: Some older SATA interfaces in computers cannot properly communicate with SATA 3.0 GB/s (commonly called SATA II) drives and determine a speed that both the computer and drive can agree on. If your computer can't handle this speed negotiation use the jumper to default the drive to SATA 1.5 GB/s (SATA I) to ensure proper communication and data transfer between the drive and the computer.

If you have the documentation for your computer you can find out if it can handle 3.0GB/s speeds or if it can negotiate another speed, or if it is limited to the original SATA spec.
posted by Science! at 12:09 PM on January 14, 2009

Response by poster: By documentation for my computer, do you mean for the motherboard specifically? I built it myself.
posted by Avenger50 at 12:12 PM on January 14, 2009

Wikipedia on SATA
According to the hard drive manufacturer Maxtor, motherboard host controllers using the VIA and SIS chipsets VT8237, VT8237R, VT6420, VT6421L, SIS760, SIS964 found on the ECS 755-A2 manufactured in 2003, do not support SATA 3 Gbit/s drives. To address interoperability problems, the largest hard drive manufacturer, Seagate/Maxtor, has added a user-accessible jumper-switch known as the Force 150, to switch between 150 MB/s and 300 MB/s operation.[5] Users with a SATA 1.5 Gbit/s motherboard with one of the listed chipsets should either buy an ordinary SATA 1.5 Gbit/s hard disk, buy a SATA 3 Gbit/s hard disk with the user-accessible jumper, or buy a PCI or PCI-E card to add full SATA 3 Gbit/s capability and compatibility. Western Digital uses a jumper setting called "OPT1 Enabled" to force 150 MB/s data transfer speed. OPT1 is used by putting the jumper on pins 5 & 6.[17]
posted by kanuck at 12:12 PM on January 14, 2009

By documentation for my computer, do you mean for the motherboard specifically? I built it myself.

posted by cowbellemoo at 12:21 PM on January 14, 2009

Specifically it would be the mobo chipset.
posted by Chocolate Pickle at 1:08 PM on January 14, 2009

If this is a recent mobo, it can handle 3.0 Gb/s. The 1.5 Gb/s limitation is specifically for older mobos, which were designed before SATA 3.0Gb/s came into being and so cannot handle the data clock rate.
posted by Susurration at 4:49 PM on January 14, 2009

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