I'm looking to get a 2.0ghz MBP, but I was wondering what harddrive to go with, the 100gb 7,200 rpm hard drive, or the 120gb hard drive? I wanna upgrade to either one, just not sure which one. Would a faster hard drive be better than one with more space, I want the one that will give be the best overall performance (battery life, speed, etc).

[Franz Josef]

Welcome thairs. It's a trade off - speed v capacity. I use a 100GB 7,200 rpm drive in my PB and there's a noticeable speed increase over the old 80GB 5,400 rpm. When I upgrade to MBP, I'm planning to stay with the faster drive.

A 100GB drive is a good size. 80GB and over is fine for a "pro" laptop.

[julesstoop]

I would go for the faster drive (actually, I did when I ordered mine) You can always get huge amounts of external drive space (in a FireWire enclosure for instance) relatively cheaply.

[Dorian Gray]

Despite frequent assertions that faster disks reduce battery life, the difference is so slight that it's pretty irrelevant. A 2.5-inch hard disk accounts for only a small fraction of a notebook's total power consumption, so even if the power consumed by the disk were dramatically reduced it wouldn't have a big effect on battery life. And the power difference between 5400 and 7200 RPM disks is just a fraction of one watt. Even if battery life is very important to you, you shouldn't choose a hard disk based on power consumption. It just doesn't matter.

A hard disk's overall speed depends on a few things, in declining order of importance: data transfer speed, average rotational delay, and average seek time. The data transfer speed depends on two factors: data density and rotational speed. If the disk is higher capacity, it will also have higher data density, resulting in faster transfer speed. So in the case of the two disks you're considering, the 7200 RPM disk has a higher transfer speed than the 5400 RPM disk, but not by as much as the rotational speeds would suggest, because the slower disk has higher data density (think of more 1s and 0s passing the heads per second as the disk spins because they're closer together). The actual data transfer rate would be about 11% higher with the 7200 RPM disk.

Seek time (the time for the read/write heads to move to the correct track) will be almost identical for both drives, therefore not important. However average rotational delay (latency - the time the heads have to wait before the rotating platter does part of a revolution so the heads can start reading the appropriate data) will be about 33% lower for the 7200 RPM disk. This means that the 7200 RPM disk will start transferring data an average of 1.4 milliseconds sooner than the 5400 RPM disk when the computer asks for data. This difference is not important in typical usage.

So it boils down to whether you want 20% extra capacity or 11% extra speed. Personally I think I'd choose the extra capacity because capacity is a bigger problem for me (with notebook disks) than speed. If you do a lot of disk-intensive work (uncompressed video, Photoshop, etc.) you may value the extra speed more than the extra capacity. For me, the value of a notebook drops if I have to keep data on an external disk - there's a lot to be said for having a big enough disk to keep everything in one convenient place. Of course if you can fit all the data you need on the 100 GB disk you can have the best of both worlds: high speed and enough space. But it's very easy to underestimate the space you'll need.

[intlplby]

has anyone benchmarked the difference in performace between a MBP with a 7200/100 and a 5400/120 yet?

i know the former has a speed advantage, but the latter had a disk density advantage (by a little)... so how to they compare?

[Franz Josef]

Originally Posted by intlplby has anyone benchmarked the difference in performace between a MBP with a 7200/100 and a 5400/120 yet?

I think that's what Dorian Gray was trying to do.

[mwe]

Originally Posted by Franz Josef I think that's what Dorian Gray was trying to do.

In theory yes, but I think Intlpbly meant if anyone has done any real world tests measuring the speed difference of the two drives.

[NosferaDrew]

I've got a 2Ghz MBP with a 100GB/5400 drive if we want to start gathering benchmarks.

[TednDi]

I bought the bigger hard drive.

[intlplby]

i have the 120/5400,

[Julian Bennett Holmes]

I would go for the faster drive, unless you really need the extra 20 GB.

2000 extra RPM will help you every day, for certain, and 20 extra GB will only help you after you've used the first 100, which is probably unlikely, at least for the vast majority of users.

Thanks for the replies everyone, I've decided to go with the 7,200rpm hd, as most of you have convinced me that the performance benefits are better with the faster hd, as well as the battery life not being affected all that much. Now, let's see if I can get one that doesn't have any defects/problems. Thanks everyone.