I've got a new hard disk. On the label there is a description of the jumper settings:
One of them is:
Jumpered pins 5 and 6 enables 1.5GB PHY
What does PHY stand for?
It's SATA II disk, right?
And if you put jumper on these pins HDDs will be SATA I.
It's there for if your motherboard doesn't support SATA II.
I bought the same disk 2 days ago. What everyone else says is right, jumpering those pins will limit the transfer rates to 1.5Gb/s rather that the 3Gb/s it is capable of.
By jumping the two pings, 5 and 6, you limit the transfer rate to 1.5 GB/s.
PHY is simply the physical layer in question, between the drive and cables/transfer.
Take a look at Wikipedia's page on SATA throughput.
PHY stands for "physical layer". By jumpering pins 5 & 6 will cause the drive to go into a legacy 1.5 Gbit/s mode, rather than its default 3.0 Gbit/s mode. Check out the Wikipedia article on SATA for a bit more info.
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