Native command queing question

Golden Ape · 22 Aug 2007 at 15:05

I'm guessing this question must have been asked before but for the life of me I can't find the answer anywhere. Basically I want to know if native command queing (NCQ) is currently working on my machine.

I have the following setup: Asus P5B mobo and Samsung HD501LJ both of which support NCQ. I've got the drive enalbed as AHCI in Bios and am running Vista 32 Buisiness. So how do I know if NCQ is actually working? I've looked around in Device Manager and can see no sign of it.

Just out of interest: I actually ended up having to reinstal Vista as I'd initially insalled with the drive in ATA mode and wanted to change to AHCI (required for NCQ). I'd followed a guide (that I can't now find) that suggested I should change a registry entry before enabling AHCI in bios. The up shot of all this was that Windows wouldn't start and wouldnt' repair. Ah well.

rpstewart · 22 Aug 2007 at 15:12

Personally I wouldn't spend any time trying to get NCQ going, in a normal single user environment the I/O queue depth doesn't get big enough for NCQ to be able to make any real improvements to the disk throughput.

Golden Ape · 22 Aug 2007 at 15:22

Mmm interesting - thanks for the input rpstewart (I was hoping you'd be around). I've come across quite a range of opinions on whether or not it makes much of difference. Does AHCI bring any benefit over just running a drive in ATA mode? I think I'm right in saying it allows hotplugging which might be handy for eSATA drives.

rpstewart · 22 Aug 2007 at 15:55

I've never used drives in AHCI mode, only legacy or RAID so I'm not sure of any real world benefits. As far as I know it's intended to be an extension to the ATA standard to allow things like NCQ to be used by generic drivers so it's really fringe benefits rather than a full on performance boost.

I've come to the conclusion that eSATA is wierd. I'm on my second board with eSATA either on the backplane or a specific internal port and neither have appeared in the safely remove hardware list :confused:

Golden Ape · 22 Aug 2007 at 16:14

Right I guess I might have been better off just leaving the drive in legacy mode - that will teach me to messy around with a stable system. Still it seems quite anoying not to be able to tell whetehr or not the much vaunted NCQ is actually active (let alone providing any advantage!)

gnetx · 24 Aug 2007 at 11:33

Golden Ape said:
Right I guess I might have been better off just leaving the drive in legacy mode - that will teach me to messy around with a stable system. Still it seems quite anoying not to be able to tell whetehr or not the much vaunted NCQ is actually active (let alone providing any advantage!)

I've moved onto an nF680i platform now, but I think I'm right in my belief that when I had my i955x the Intel HDD management tools allowed me to see the NCQ status of the drives... might be worth a look (was it Application Accelerator that had such info?). You've probably given up on your quest for this info now anyway, but thought I'd offer my 2p...

Golden Ape · 24 Aug 2007 at 12:37

Ah thanks. I haven't given up quite yet! I'm not quite clear what you mean by Intel HHD management tools though. Do you mean device manager > hard disk?

edit: Right I see what you mean by the Application Accelerator. Doesn't appear that there's a version for Vista though. Hmmm may be I should give up on this, it's already cost me one reinstall.