Momentus XT 750 is slow

I've been installing apps onto the new Momentus XT 750GB drive I bought 2 days ago. CS5.5 Suite normally takes ~55 minutes, but the time indicator read a very atypical 148 minutes. It started to go down, but has stabilized at 111 minutes as of this point, but just went back up to 117.

Never, in any CS5 install, has the installer ever reported over 100 minutes.

Even a restore of 200GB, which I knew would take time, remained at "about 3 hours remaining" and took far more than an hour to get to "about 2 hours remaining", so even network transfers are seemingly slower; I can rule out the optical drive...

A web search revealed nothing of substance... but http://www.laptopmag.com/reviews/storage/seagate-momentus-xt.aspx does say large files can be a drag... most of my files are <50MB, with only three VMs really taking up gigabytes of space... apart from installer files downloaded as there was no DVD option... that article suggests an issue, but I don't think that's a sufficient explanation; Adobe installs typically take 50~70 minutes. Never 90~117(or the brief '148')...

Drive Genius 3's sector scan checks out fine.

Could this model just be slower with write access?

I did install Snow Leopard and then upgraded to Mountain Lion over it... in both cases, the installer would read "29 minutes..." , go up to "34" minutes", stay at "34 minutes" for a few minutes, and then would remain accurate... something seems amiss.

Is this just normal drive write performance (read times are phenomenal) or did I put a bad unit into the shopping cart?

 

Thanks for the URLs. I will check them out and run tests to confirm if the unit I bought is defective, via the benchmarks. I might just be paranoid or something, as I've not re-installed anything big on a Mac in a while... It's shaved off 60 minutes off the tally in 25 minutes, so that's a good sign... or not a bad one...

True.

I first wondered if there was a problem with the unit I bought, since even the stock HDD - Apple's 750GB 5400RPM model, didn't show such agonizing "time remaining values"...

But I did manage to find this, though:

http://www.hardwaresecrets.com/article/Seagate-Momentus-XT-750-GB-Hybrid-HDD-Review/1474/3

That confirms the Momentus, for write speeds, is substantially slower than non-hybrid HDD competitors (including one of Seagate's own! )

So I'm starting to believe the unit I bought is not a potential dud, and that this Momentus XT model just has slower write times (10~14% slower overall). If that's the case, I can dig it and get on with life. For single files, I won't notice write times, and I bought it for the hybrid/rapid OS loading times (and the original drive can be in storage as a backup...)