I'm about to build a PC for the first time. I'm planning to use an SSD for the operating system / critical applications, and a HDD for the rest. One of the main things I plan to use the system for is music-making, and partly for that reason I'm interested in building a system that is as quiet and cool as possible.

My question is this: until recently it's been considered desirable to use fast HDDs for music / recording purposes - the faster the better, really. However, it occurred to me that since I will most likely have 16GB of RAM, this advice may no longer hold. Presumably a large amount of RAM means a huge amount of audio buffering capacity. In which case (and given that the OS and critical applications will be running from SSD) is the speed of the HDD I'm recording to likely to make much difference? In fact, given that a slower HDD (say 5400RPM instead of 7200RPM) would be quieter and generate less heat, could it be that - counterintuitively - these advantages might actually outweigh the slower read/write speed?


The RAM doesn't really "Buffer" the data that is to be written to the disk. However your applications work to load data from the hard drive into memory, when you have data that is to be written to the disk that is done nearly immediately, depending on how busy the system is. Buffered writes are only very short term.

The faster your hard disk is, the quicker it will complete the operations it performs. So, for a given read/write operation, a faster hard drive will be "active" for less time than a slower drive. So while it may consume more power, it does so for a shorter amount of time. Overall power consumption may be more, less, or the same depending on your usage habits.

In my experience, once you have "enough" RAM, having more RAM will not help hard drive performance. My current computer is quad-core with 8GB RAM. Usually RAM usage peaks at about 4GB. It rarely goes above that. If it has been running for a few days without rebooting, it may get to 4.5GB or slightly more. Only if a program is "misbehaving" (preparing to crash) will RAM usage increase significantly above that. Of course, that's only "my" experience. It could be that the applications that I run are just not demanding enough on memory to take advantage of the full amount of RAM.

Even copying 200 GB from one physical drive to another will not noticeably increase RAM usage. It is purely dependent on drive speed.

I think overall, you shouldn't sacrifice speed for power, especially on a computer with only 1 or 2 drives. As time goes on, more and more applications are more demanding on RAM and disk activity. Eventually you will wish you had purchased the faster drive. If you have many computers with many drives then of course, power and drive cost may be a more significant factor.

If you are concerned about noise and power consumption, you could look into some of the "green" drives. I have no experience with them, but I believe some will normally run at 5400 RPM and will increase their RPM as demand increases (probably up to 7200 RPM). That could be a good balance between power, noise, and performance. I have been planning to try one of these the next time I need a new drive.

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Sequential read/write performance on any modern hard disk is fast enough to record uncompressed high quality audio without problems. A 5400 RPM will do drive and it will generate less heat, produce less noise and draw less power.

The main advantage of higher spindle speed drives is in random access. If you work on one song, or if you are not doing a dozen simultaneous things (such as running torrents in the background) while you edit your music then a 5400, 5200 or 3600 RPM drives will do just fine.

( Especially with the OS already on a different drive -The SSD- )

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  • Short answer: yes. – Isaac Rabinovitch Nov 8 '12 at 1:53
  • Higher spindle speed has no direct effect on the speed of random access operations. Improvements in random access operation will be gained from quicker head motion times (access time). Higher spindle speed affects data throughput... more data sectors read/written per second... but only after the head is positioned at the desired track. – Kevin Fegan Nov 8 '12 at 2:54
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    I disagree. Moving to a new sector requires moving the heads to a new cylinder and waiting for the disk to rotate until the right sector is under the head. On average this takes half a rotation, which takes less time is the disk spins faster. Therefore rotation speed is part of the equation. – Hennes Nov 8 '12 at 3:00
  • Yes, but this is the case even if you are already positioned on the desired track ... you still have to wait for the desired sector to rotate into position. So it is just a function of the basic advantage of a higher spindle speed. It doesn't get you any "extra" advantage for random access compared to sequential access. – Kevin Fegan Nov 8 '12 at 3:19
  • I've mulled this over several times. I can see why you consider it part of faster (sequential) data transfer once the head has moved. And I still consider it faster random access because you have to wait less time when you move to a new random track. One which is probably not yet buffered. And the latter can even throw off both or reasoning. Some firmware might as well buffer entire tracks, regardless of requests. Bottom line however is that we both agree that higher RPM drives are faster. – Hennes Nov 8 '12 at 15:15

If you are doing music-making, you might want to play multiple audio files/tracks at the same time. The speed of your hard disk will limit how many of these you can play simultaneously (also depending on the quality/format of the audio). In this case disk seek time will come into play.

If you only plan on playing/recording one track at a time, however, any modern hard drive should be able to cope easily.

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