A little tip for those of you who might have installed Seagate SATA drives into your 3GB/s capable G5, MacPro, NAS device, or whatever.
Looks like recent Seagate drives ship with a jumper installed that limits the drive to 1.5GB/s speeds. While the jumper is documented in the User’s Guide that ships with retail packs, it’s specifically mentioned as something you might need to install if you have trouble with the drive. And OEM drives don’t have any documentation at all.
To get 3GB/s, the jumper should not be present on the outer pins of the jumper block. So — if you’ve got one of these drives, check it out: you might get that drive humming along twice as fast!
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I'm not sure this matters in the real world, at least as far as throughput is concerned. Today's drives should max out at much less than 1.5Gbps.
It actually made a huge difference on my system: I think that the Seagates (as opposed to some other brands) slow things down more than expected in this mode.
Really: it was quite significant. If you have a Seagate, a 3MB/s controller and the jumper in place, give it a try.
Thanks for the tip, but shouldn't that be GB instead of MB?
Ah, indeed. Duh. Will fix.
Was this in a Mac Pro?
Two drives in a MacPro, two drives in an external RAID device I'm currently testing.
Somehow I doubt it will make significant performance impact unless the jumper also turns off things like NCQ. 1.5 GB/s translates to a theoretical transfer rate of 192Mb/s even if you substract overhead and such that is about twice as fast as the quickest sata drives on the market. Or am I missing something?
I realize that the native speed of the interface is faster than the drive. However, it does make a difference with these Seagate drives. Why that might be is difficult to determine because we really can't tell what it's doing [b]in addition[/b] to the speed difference.
It's quite possible that it turns off NCQ as well, or does other things that slow down the drive's performance. I can only tell you what I found -- performance is significantly enhanced without the jumper.
Is this a little *too* weird to anyone else? Just planning a RAID array as a consumer is far more difficult than it has to be. I wonder what other little quirks we'll see from the other brands this round.
hi there
is there anyone who can categorically state whether or not taking out the jumper does in-fact turn off NQC?
i've bought a bunch of these drives recently and put them in external firewire and usb enclosures - mainly for use with macbooks
as i didn't know where these enclosures (containing bootable volumes) would end up i didn't want to throttle back the drives throughput, but NOT at the prospect of reduced performance (ie no NCQ)
any info would be greatly appreciated
thanks
I don't think removing the jumpers would possibly turn [b]off[/b] NCQ...
thanks dave - BUT, "I don't think..." is still not definitive!
thanks again ; )
r
I bought two, and they have the jumper blocks. What more, they're advertised as 3gb/s, but the limiter jumper can't be removed. It's this stubby little thing that seems to be permanently affixed to the pins. Can this be removed, or do I have to desolder the pins themselves?
They can be removed -- they're short jumpers, but do come off.