WD6400AAKS vs WD6400AACS

[Ararat]

Hi guys, I just bought a Western Digital 640GB HDD, as I've been very pleased with them in the past. I have a RAID 0 array of 2 of these drives, and wish to add a third to migrate it to a RAID 5 array (with a mind to eventually add a fourth drive for a little wiggle room).

To my horror, it turned out to be a WD6400AACS, one of those 'Green Power' drives. Once I had finished cursing the left wing hippies who had dreamed up such a device, I set about searching google for how much this was going to cost me in terms of performance. Unfortunately, I'm not having much luck finding a review of this drive. There are plenty of reviews of the 750 GB GP drive, but that uses platters with an inferior areal density. Does anyone have any numbers, or at least a reliable estimate of the difference in performance?

What I really want to know is how much performance I'm gonna lose by having this GP drive instead of the AAKS, and also, will it prevent the other drives in the array from exploiting their full potential? One would presume that migrating this present array with this drive would improve performance, but not by the nearly 50% I would see with an AAKS.

Should I take it back and hunt around for an AAKS?

Thanks for any help.

 

[AmongthechosenX]

Green Power drives are great... FOR STORAGE PURPOSES ONLY. they NEVER run at 7200RPMs, usually between 5400-6000RPM's.

the access time on those drives are HORRIBLE. Compared to an AAKS, you are probably losing alot of performance, especially when you consider that you are using RAID.

Run HDtach (google it for the download), and post a screen shot of your results. I'll stack it up to my own and see what youre getting.

 

[Engineer]

Originally posted by: AmongthechosenX
Green Power drives are great... FOR STORAGE PURPOSES ONLY. they NEVER run at 7200RPMs, usually between 5400-6000RPM's.

the access time on those drives are HORRIBLE. Compared to an AAKS, you are probably losing alot of performance, especially when you consider that you are using RAID.

Run HDtach (google it for the download), and post a screen shot of your results. I'll stack it up to my own and see what youre getting.

It's a marketing gimick. They run at 5,400 rpm and NEVER change. WD has removed the reference from their website after many testing sites ran tests to prove that GP = 5,400 rpm drive. Doesn't mean it isn't fast as it has high density platters but it won't be as fast as a 7,200 rpm drive. It will be quieter (typically) and run cooler though.

 

[DrBombcrater]

I just bought both a 6400AACS (GP) and a 6400AAKS (SE16) this week along with some other drives and I've been doing subjective tests by imaging a really cruddy Vista install on to them and playing about with it. Both WD drives feel very quick, the SE16 being the snappier of the two but not by as much as I expected. The GP doesn't feel like a 5400rpm drive, it feels like a slightly below par 7200 - I wouldn't worry overmuch about your array being slowed down by it. It's noticeably quicker than a couple of older 7200s in the same machine (400GB Samsung T166 & 500GB Hitachi 7K500) but not a fast as the 500GB Seagate 7200.11 that's also in there. TBH, I'm impressed to get that kind of performance from a drive that's basically silent and will run on a desk with no airflow all day and barely get warm.

Don't have HDTach to hand, but Sandra rates the GP at 15ms and 70MB/sec average, the SE16 at 13ms and 83MB/sec. Only got one of each drive so can't run any tests in RAID.

(For a giggle I tossed one of Hitachi's "green" P7K500s in to see how it compared to the GP. 76MB/sec and 19ms average. It feels like a slug and gets roasting hot. It's already boxed up waiting to go back. Congrats to Hitachi for making a 7200 that can't keep up with WD's 5400 :frown: )

 

[Ararat]

Thanks guys. I couldn't run my own tests as I have yet to open the foil wrap (I plan to take it back if it's too crap). That's why I hopped on here.

Just for the record, the access times do not concern me too much, I am more interested in average sequential read/write performance, as I use this machine for video editing, and when I've got ~30 jobs in the queue, including HDTV it can take a while.

The reason why I asked if it would affect my RAID array, is because when files are striped across the 3 hard drives, I thought it would be pointless if the other 2 drives are faster, as to get the complete file, it would have to wait for the slower drive to deliver an equal amount of data. Then again, I'm probably thinking in RAID 0 terms.

With that sort of performance difference (what is it, 15-20%?), I think I'm leaning towards keeping it. I guess less heat and power consumption are a good thing, though less noise means nothing when you consider that it will go into a machine that already has 4 other hdd's, an 8800gt, and a TRUE cooling an oc'd Q6600 - it's voice would have just gotten lost in the choir anyway.

Thanks guys (esp Bombcrater for providing numbers).