[Ti] Need new HD for my TiBook

[Kynan Shook]

Sure, I did some research to help folks out...  All this info is from  
the respective manufacturers' websites for a variety of drives,  
though not exhaustive.  In general, they don't list different power  
consumption for different drive capacities, probably to reduce the  
testing they have to do.  I'll list two power requirements for each;  
first is Idle (eg, disks spinning, but no reading/writing - what your  
drive is doing almost all the time) the second is reading.  All  
values are typical.  Also listed are the maximum capacity of the  
drive model, the interface type (SATA is generally a couple tenths of  
a watt more than parallel ATA), and the rotational speed.  Enjoy:

Seagate:
120 GB Ultra ATA 5400 RPM: 0.8W idle, 1.8W reading
120 GB SATA 5400 RPM: 0.8W idle, 1.9W reading
160 GB Ultra ATA 5400 RPM: 0.8W idle, 2.0W reading
100 GB Ultra ATA 7200 RPM: 1.3W idle, 2.2W reading
100 GB SATA 7200 RPM: .95W idle, 2.4W reading
160 GB SATA 7200 RPM: 1.3W idle, 2.1W reading

Toshiba:
200 GB SATA 4200 RPM: .85W idle, 1.85W reading
120 GB Ultra ATA 4200 RPM: 0.7W idle, 1.6W reading
120 GB Ultra ATA 5400 RPM: 0.85W idle, 1.9W reading

Hitachi:
100 GB Ultra ATA 7200 RPM: 1.1W idle, 2.0W reading
100 GB SATA 7200 RPM: 1.2W idle, 2.3W reading
100 GB Ultra ATA 7200 RPM (high reliability version): 1.8W idle, 2.0W  
reading
100 GB SATA 7200 RPM (high reliability version): 2.1W idle, 2.3W reading
160 GB Ultra ATA 5400 RPM: 0.8W idle, 1.8W reading
160 GB SATA 5400 RPM: 0.85W idle, 1.8W reading
120 GB Ultra ATA 5400 RPM: 0.75W idle, 1.8W reading
120 GB SATA 5400 RPM: 0.85W idle, 1.8W reading
120 GB Ultra ATA 4200 RPM: 0.65W idle, 1.4W reading

Samsung:
160 GB SATA/Ultra ATA 5400 RPM: 0.6W idle*, 2.0W reading
*Samsung gives low-power idle, meaning the read/write heads are  
parked and the R/W circuitry is off.  All the other drives are listed  
with active idle, where there is no extra power needed to move the  
heads and begin reading again, and the read circuitry is still  
active.  The only company that gives both is Hitachi, where the  
difference was generally an extra 0.2W of savings when moving from  
active idle to low-power idle.

So, taking that note into account, the numbers for all manufacturers  
are very close to each other; higher RPM drives definitely take more  
power, but it's not much in the grand scheme of things.  SATA drives  
also usually take more power, but not always.

In terms of battery life, it probably won't be noticeable.  If you  
get 3 hours on a 55-watt-hour battery, you're using 18.33 watts.   
Now, say you change your drive from a 4200 RPM one to a 7200 RPM  
drive, and increase power consumption by 0.67 watts on average.  That  
would chop about 6 minutes of battery life over the course of 2  
hours.  About 3 years ago, I did some power measurements on 12 and 17- 
inch 1 GHz PBG4s, and found that you could save about that much power  
just by turning off Airport.  The display alone at full brightness  
used about 8W on the 17" PB (or 4W for the 12").  Even with the  
backlight off but the display still active, the displays used 1 to  
1.5W more than when Energy Saver turned off both the backlight and  
the display itself.  The CPU's power could jump by as much as 12W  
when used at 100% versus when idle.  The moral of the story?  It'll  
buy you a few extra minutes (especially because the hard drive is  
generally always on), but unless you already are squeezing every  
minute out of every other system in your laptop, it's probably not  
worth buying a drive simply because it uses less power.


Longing for the days when you could boot from a RAM disk and unmount  
your hard drive,


Kynan Shook
kashook at wisc.edu
http://homepage.mac.com/kynan/


"Dr. Trevor J. Hutley" <TrevorHutley at consultant.com> writes:
> On 21 Jan 2007, at 15:58, Matt Kibildis wrote:
>
>>  in my experience (I deal with these things everyday), Samsungs
>> operate at a much cooler temperature, which is better overall for
>> the other components in your laptop.
>
> Matt - that is a very interesting observation.  If the drives run
> cooler, then they use less energy and so battery life is longer (as
> well as the benefit of a cooler laptop on the lap and improved
> environment for other components).
>
> Has any one ever checked the power consumption (specifications) of
> like-for-like disks?  [same size, same speed]
>
> This could be a new source of differentiation for hard disk
> manufacturers (in addition to size, speed, cache size, guarantee and
> of course price).
>
> Anyone else got ¢2 on this issue?