As hard drive fills up, computer performance decrease (True or False)?

[bchamorro]

I just ordered a new Mac Book Pro (4GB RAM, 320 7200 RPM hard drive).

My iTunes library is about 200GB because I ripped all my CDs in Apple Lossless.

Will it be ok if I move my 200GB Library to my MBP's 320GB 7200 RPM hard drive? Or will I notice a big decrease in performance? I also have about 20GBs of pictures and movies, but music is more important.

The other option I have is to play my iTunes Library from an external hard drive using eSATA (FireWire 800 por is taken), but it would really suck to move around an external and connect it every time to listen to iTunes.

 

[wordmunger]

You shouldn't have a problem as long as you don't go over 90 percent of your disk space. You need to have enough room left over for virtual memory. But if you've got a good chunk of free space (32 GB should be more than enough) you'll be fine.

 

[sammich]

The performance decrease happens because data becomes spread all over the hard drive. When you put something on the hard drive it'll basically fills in gaps (free space) in the hard drive.

This effect doesn't happen until you consistently add and remove a lot of files, especially as it gets full.

Regarding memory on the hard drive 'virtual memory'. It will slow down your computer as it will use your hard drive for memory access and for your normal file reading.

 

[smacman]

As wordmunger said, keep at least 10% of the drive free and the drive will perform near optimum... If you do start using the last 10%, the drop off in performance is quite noticeable in OS X.

 

[TheKnifeFight]

i'm trying to keep my drive fairly clean by using an external..but you should be good as long as you keep a chunk free.

 

[IJ Reilly]

False. As long as you have around 5 GB available for virtual memory swap files, you should be fine. I don't understand why so many people say it should be a percentage of the drive. It doesn't work that way.

 

[lancestraz]

False. As long as you have around 5 GB available for virtual memory swap files, you should be fine. I don't understand why so many people say it should be a percentage of the drive. It doesn't work that way.

According to this article that pits a SSD against a conventional HDD, conventional HDDs do slow down as they fill up.

The first two graphs above show what happens when each drive fills up. The OCZ SSD maintained its transfer speed no matter how full the drive became. Conventional hard drives get significantly slower as the drive fills up. The Hitachi 7K320 we tested dropped from 75MB/s at 0% to 44MB/s at 90% capacity.

 

[mknawabi]

lance is correct, the read/write head has to travel further than normal in order to access or write data at the outermost areas on the platter of the disk.

 

[IJ Reilly]

Yes, but if the question is how much space you need for virtual memory swap files, this does not change depending on the size of the drive. They take up the same amount of space irrespective of the capacity of the drive. If you're running a relatively small amount of physical RAM, it would not be unusual to generate 2 GBs of swap files in a short time; more if you can stand the performance hit and don't reboot the Mac.

 

[ManWithhat]

The read/write head has to travel further than normal in order to access or write data at the outermost areas on the platter of the disk.

This is mostly correct. Think of the hard disk as a CD with little 1/2 inch marks all over it with with quarter inch spaces between them. If I wanted to add a 1 inch file and the drive was nearly full, it may not be able to store in a new location and is going to have to put the file between other files (in those quarter inch spaces). These spaces on the hard disk might be towards the middle of the 'CD' or at the outer edge. What this means is when we want to load that file into memory, the head (think of it kind of like a pendulum) has to move a lot more to read the entire file (which is broken/scattered into those multiple smaller spaces rather than all in one spot).

This doesn't happen with SSDs because they have no moving parts (there is no head). So if the file is scattered, it can read parts from different locations without losing time.

 

[Pressure]

Traditional harddrives most definitely slow down as they get filled up.

 

[wordmunger]

According to this article that pits a SSD against a conventional HDD, conventional HDDs do slow down as they fill up.

Interesting. I didn't know that. But there are really still two separate issues, though -- there's the issue of having enough room for your swap files, and the issue of gradual slowing as the HD fills. The first problem slows your computer dramatically, the second problem is a much more gradual, and less noticeable effect. Looking at the linked article, even filling the HD halfway will slow it down quite a bit. If you want a really fast HD, don't put anything on it at all. But then, what would be the point?