Does storage capacity affect hard drive performance?

"A generalisation isn't useful, but mostly when talking similar models/same series I'd say the larger drive would be faster due to higher data density in some way (be it more platters and heads, or just denser platters).

The bigger model would likely be newer as well and could benefit from firmware and other production improvements.

This is even more true in the world of SSD where the larger capacity options are generally faster due to more parallelism. On the other hand, sustained throughput isn't always the important factor of an SSD compared to mechanical drives but rather the low-latency on small random access read/write - which will be the same in most scenarios regardless of the number of chips."

"You can not. Drive speed depends on lot of things, mostly on disk data density (is rotational speed is equal).

If you can, between two disks with same capacity, use one with lower number of platters."

"In general I agree everyone else's answers. Given two hard drives with all else being equal the drive with greater data density will outperform the one with lower data density.

I can think of two scenarios where a larger drive capacity is a detriment to performance. In both cases it is not the drive that's the bottleneck but the file system.

Formatting the drive

This is simply a matter of common sense. Since formating touches every byte on a drive a larger drive capacity will take longer to format. Since this is usually only done during an OS installation its not really a problem. In most cases its unnecessary to perform a full format operation anyway.

Bumping into the limitations of the file system in-use

The best example of this was the point when drive capacities started to push the limits of the FAT file system. Without getting too technical FAT was designed for disk capacities a fraction of the size of its theoretical limits. FAT16's limit was around 2GB but as partitions approached this limit not only did they waste significant amounts of space but the overall performance of the file system degraded. FAT32 broke the 2GB barrier and performed better than FAT16 but ran into the same problem when drive capacities started approaching its theoretical limit (its around 2TB but this would be laughable to even attempt)

Each file system has different best and worst case running conditions. Modern file systems are designed to at least maintain performance if not improve it as drive capacity grows at the expense under-performing on small drives. A reasonable trade-off considering drive capacities are continuing to grow."

"A hdd has a few platters. If both 80g and 500g has the same number of platters. That would mean the OS installed would fall in several platters on the 80G where as 1 or 2 platter on the 500G.

Each platter would have its own read and write. So on the 80G it is serviced by more heads than the 500G. So it is faster."

"Does storage capacity affect hard drive performance?

Purely based on storage capacity: No.

However a bigger drive (as in, with more storage capacity) tend to be more modern and faster. So in practise: often yes.

From a mechanical point of view, and assuming rotating rust:

A drive is faster is it spins faster (more RPM). This means more platter spinning below the the r/w head in a period of time and less time waiting for a sector to arrive under the head.
A more modern drive often has higher data density. Think of it as reading a book (at the same speed). When you write in smaller letters you can read/write more of them at the same distance.
More modern drive tend to be bigger and have other technological advantages (e.g. faster head movement).
Drive with more platters are often faster because a head switch is faster than waiting half a rotational time. And more platters more bigger capacity."