Hard drive performance
- Thread starter Miki5000
- Start date
Yes 10-20% would be a lot however you are no where near the right numbers. Like I said, the hard drive takes so little energy that your looking at less then 1%. Especially since its just the difference of 1800 RPM which is not much at all.
http://www.notebookforums.com/t/118667/5400-rpm-vs-7200-rpm-power-consumption-performance
Once the platters are spinning at 5400 or 7200 RPM, the only energy the motor has to deliver is sufficient energy to counteract that lost to the friction of the bearings. You may remember from physics class that friction is proportional to the coefficient of friction and the normal force, but has nothing to do with the speed between the two objects? Thus, it costs no more energy to sustain 7200 RPM than it does 5400 RPM.
The extra power at startup probably comes from the fact that the 7200 drive takes no longer to spin up than the 5400 drive, but has a higher RPM total to reach. Since the motors are having to create a higher rotational acceleration during spin-up (more "RPM's per second"), the 7200 drive's motor will use more energy.
This extra energy isn't used to offset friction; it goes into the rotational kinetic energy of the platters, opposing their rotational inertia -- you may remember that the kinetic energy for a spinning object is equal to 1/2 I w^2, where I is the moment of inertia and w (omega) is the rotation rate. So another way to look at it is that the 7200 RPM drive has more kinetic energy while spinning, so the motors have to provide energy at a higher rate (power) to spin it up in the same timer.
Once the platters are spinning at 5400 or 7200 RPM, the only energy the motor has to deliver is sufficient energy to counteract that lost to the friction of the bearings. You may remember from physics class that friction is proportional to the coefficient of friction and the normal force, but has nothing to do with the speed between the two objects? Thus, it costs no more energy to sustain 7200 RPM than it does 5400 RPM.
The extra power at startup probably comes from the fact that the 7200 drive takes no longer to spin up than the 5400 drive, but has a higher RPM total to reach. Since the motors are having to create a higher rotational acceleration during spin-up (more "RPM's per second"), the 7200 drive's motor will use more energy.
This extra energy isn't used to offset friction; it goes into the rotational kinetic energy of the platters, opposing their rotational inertia -- you may remember that the kinetic energy for a spinning object is equal to 1/2 I w^2, where I is the moment of inertia and w (omega) is the rotation rate. So another way to look at it is that the 7200 RPM drive has more kinetic energy while spinning, so the motors have to provide energy at a higher rate (power) to spin it up in the same timer.
Quaddro
Distinguished
- Sep 1, 2010
- 2,074
- 2
- 20,965
okay..what about this..
well, consume 20% more power than traditional low wattage 2.5 harddrive..
Every point of wattage, affecting battery life.
Okay, maybe not drastically..not 10%-20% for whole system. but at most 5%..
i'm wrong at this point..
well, consume 20% more power than traditional low wattage 2.5 harddrive..
Every point of wattage, affecting battery life.
Okay, maybe not drastically..not 10%-20% for whole system. but at most 5%..
i'm wrong at this point..
Got a bit off message guys, but thanks for you input. There will be two of these drives will form a RAID 1 array for an entry level server, not a laptop, so performance is the key here. No SAS available before you suggest it - thanks again
TRENDING THREADS
-
-
-
Question Help in troubleshooting possible graphics card issue?
- Started by nort99
- Replies: 5
-
Question RX 6600 visual glitches right after upgrading to it- Started by Wamek
- Replies: 4
-
News US sanctions transform China into legacy chip production juggernaut — production jumped 40% in Q1 2024- Started by Admin
- Replies: 35
-
Facebook
Twitter
Instagram