3 ms·

> With the variable speed drives (WD Green) None of Western Digital's HDDs change their RPM. It is fixed.

curun1r 12y ago
The WD docs for Intellipower indicate that RPM is one of the things they vary to conserve power. I can't find much in the way of specifics, but since they list the RPM of the drives as "Intellipower", the assumption would be that they don't operate at a fixed RPM.
- arthurfm 12y ago
  The RPM varies between different models. Each drive has a fixed RPM [1][2]. From SPCR: > Western Digital doesn't want to say that they're selling 5,400 RPM drives — those became second class in the desktop market years ago. Instead, they rate the drive's speed as "IntelliPower" and take pains to emphasize that there are other factors that affect performance. Western Digital has caught a lot of flak for withholding the rotation speed of the Green Power, especially when the product was first launched and the marketing material listed the rotation speed as 5,400-7,200 RPM. This led some to speculate that the rotation speed changed dynamically during use — which would have been an impressive engineering feat had it been true. The reality is revealed by a sentence that Western Digital added to the description of IntelliPower: "For each GreenPower™ drive model, WD may use a different, invariable RPM." In other words, Western Digital reserves the right to release both 5,400 RPM and 7,200 RPM drives under the Green Power name — without telling you which are which. We were able to confirm that our 750 GB Green Power had a spindle speed of 5,400 RPM by analyzing its sound spectrum. Why sound? Sound is vibration; the pitch of the sound corresponds to the frequency of the vibration. Hard drives vibrate at the speed of their motor, so they produce a noise at the same frequency as their rotation speed. Our sample had a sharp spike at exactly 90 Hz (cycles per second). Multiplying that number by 60 (to get cycles per minute) yielded a measured rotation speed of 5,400 RPM. [1] http://www.silentpcreview.com/article786-page2.html http://www.silentpcreview.com/article786-page2.html [2] http://arstechnica.com/civis/viewtopic.php?p=23526214#p23526214 http://arstechnica.com/civis/viewtopic.php?p=23526214#p23526...

The WD docs for Intellipower indicate that RPM is one of the things they vary to conserve power. I can't find much in the way of specifics, but since they list the RPM of the drives as "Intellipower", the assumption would be that they don't operate at a fixed RPM.

arthurfm 12y ago
The RPM varies between different models. Each drive has a fixed RPM [1][2]. From SPCR: > Western Digital doesn't want to say that they're selling 5,400 RPM drives — those became second class in the desktop market years ago. Instead, they rate the drive's speed as "IntelliPower" and take pains to emphasize that there are other factors that affect performance. Western Digital has caught a lot of flak for withholding the rotation speed of the Green Power, especially when the product was first launched and the marketing material listed the rotation speed as 5,400-7,200 RPM. This led some to speculate that the rotation speed changed dynamically during use — which would have been an impressive engineering feat had it been true. The reality is revealed by a sentence that Western Digital added to the description of IntelliPower: "For each GreenPower™ drive model, WD may use a different, invariable RPM." In other words, Western Digital reserves the right to release both 5,400 RPM and 7,200 RPM drives under the Green Power name — without telling you which are which. We were able to confirm that our 750 GB Green Power had a spindle speed of 5,400 RPM by analyzing its sound spectrum. Why sound? Sound is vibration; the pitch of the sound corresponds to the frequency of the vibration. Hard drives vibrate at the speed of their motor, so they produce a noise at the same frequency as their rotation speed. Our sample had a sharp spike at exactly 90 Hz (cycles per second). Multiplying that number by 60 (to get cycles per minute) yielded a measured rotation speed of 5,400 RPM. [1] http://www.silentpcreview.com/article786-page2.html http://www.silentpcreview.com/article786-page2.html [2] http://arstechnica.com/civis/viewtopic.php?p=23526214#p23526214 http://arstechnica.com/civis/viewtopic.php?p=23526214#p23526...