"I currently have two hard drives in my HTPC - a WD 4000KS which is fine but I also have an older Hitachi 160GB 180GXP series drive that has quite a bit of idle hum/resonance which I would like to replace."
Hitachi 160GB 180GXP? There was a 180GXP but it was prior to Hitachi acquisition of IBM storage department. Hitachi drives started using 7Kxxx format for their models. Maybe they continued to manufacture 180GXP for some period of time (7K250 was already designed under the old rule but released under Hitachi brand) under Hitachi's name... or did they?
Was there a 160GB variant of 180GXP? AFAIK, they were drives with 60GB/platter, thus capacities like 60, 120 and 180 if fully populated or 80GB (cut down from 120GB) and 30GB (only one head on one platter). Hitachi web site doesn't mention 160GB variant.
http://www.hitachigst.com/hdd/support/table3.htm
Why I ask these questions? Only because I suspect it's a Hitachi 7K250 160GB variant (not IBM or Hitachi 180GXP). 7K250 160GB variant is 2 platters, 4 heads. Density 80 GB/platter.
"The hum is not there with the WD drive only."
Is it there with the IBMtachi drive only? Because it might be just a result of two drives interacting and producing a vobbling on/off vibration that is more easily perceived than a constantly on vibration. (Also, it's about twice as loud, if the drives were identical which they most likely are not.)
Decoupling / elastic suspension could help?
"I'm looking at a mid-range drive - doesn't have to be ultra-quick (although quicker than the current drive would always be good since it's my boot/OS drive ) around the same capacity. I've got a WD 160GB 1600JS (160GB SE) or a Hitachi 160GB TK250 on the shortlist."
Assuming decoupling didn't reduce perceived noise level enough, a new drive might be a solution. At 160GB capacity point I'd probably replace T7K250 160GB variant (2 platters, 3 heads, 120GB/platter) with 7K160 (1 platter, 2 heads, 160GB/platter). Also I'd replace 1600JS with 1600AAJS. AAJS should be 1 platter drive where as "non-AA" are 2 platters at 80 or 125 per platter density - I really don't know.
Other 160GB drives with one platter are Seagates (even the very old 7200.9 160GB is single platter drive). Seagates don't support Automatic Acoustic Management though: PATA models are permanently silent & slow, SATA models are noisy and slighly faster (but not fast, since Seagates have poor firmware optimizations for desktop use).
There's also quiet two-platter drives... like P-series Samsungs. If you use the current 160-gigger for OS and applications only, you could probably replace it with a smaller P80 80GB. Those are very nice (providing you get one with Nidec motor and not with JVC). If 160GB is required: P80 160GB, P120 200GB or P120 250GB (all have two platters).
Vibration is much related to sample variance, unfortunately. One never knows what one is going to get, no matter how many reviews they have read beforehand. Even 5-platter monster can vibrate less than a single platter drive... if the owner of the 5-platter monster just happens to be very lucky.
You could buy another 400-gigger to replace the 160-gigger. That way you don't have to upgrade your system so soon. Or buy a 320-gigger as they are currently so cheap. There's some 2-platter drives with that capacity: Seagate and Hitachi. (I'd prefer the latter.) WD's 320-gigger is nice too despite having three platters. The reason behind this idea is that a drive with 3 platters doesn't (usually) vibrate 3 times more (and it doesn't have 3 time heavier spindle assembly) because there is some constant weight, noise and vibration produced by the imbalance of the spindle motor itself, even it didn't have any platters attached to it. So, if you're going to add more capacity some time soon, better replace the 160-gigger with a bigger one than add a third drive later on.
Csoszi,
"I have a 3200JB (Caviar SE, ATA100); it's terrible when compared to a 3200KS."
I don't doubt your anecdotal evidence but I have opposite evidence: my WD3200JB is one of the most phenomenal quiet seekers I have. Quite close to my P80 and PL40 and definitely the quietest amongst my other 3 platter drives (7K250 and DM+9 250GB). Comparing WD3200JB against 1 platter drives already proves my sample is quite silent in operation.
There's a lot of conflicting anectodal evidence regarding WD3200JBs noise levels. There's people who report it silent, and there's people who consider it much noisier than corresponding KS variant.
Csoszi,
"And do NOT trust the dB values on the WD site: copy/paste numbers!"
I wouldn't trust any dB values, on any manufacturer's web site. They simply don't tell the truth (even if they were all measured at the same distance, with the same weighting and by some third-party) in a meaningful way. It's good to have SPCR to evaluate them both with objective and subjective means.
PS.
I'm still considering of making my own "HDD review" thread of my own drive samples. Idle, seek and vibration included. I'm just wondering what would be the best way to evaluate vibration accurately.
) around the same capacity. I've got a WD 160GB 1600JS (160GB SE) or a Hitachi 160GB TK250 on the shortlist. From web research, it looks like both perform about the same, with the WD possibly being slightly quieter. I want a drive with AAM and definately one that does not have the same idle hum as the current drive. I unfortunately can't get hold of Samsungs in my part of the world so that's not an option.