Performance can very quite a bit between drives of the same family.
Hard drives read from all the heads at the same time, so all things being equal (RPM, data density, drive mechanics) the larger drives with more platters tend to be faster ( and nosier).
However things are hardly ever equal, and the drives in a family are often very different from each other. That is to say they are not simply the same drive with a variable number of platter.
Also mixed in with the smaller drives are some salvaged rejects from the production line of their larger cousins, with some of the heads disabled.
So you have get buy two of the "same" model drives and get different performance and acoustic results.
---
Finding benchmarks for the smaller drives is often difficult.
Hard drive manufacturers always try to release the largest and fastest drive in the family first, which then gets reviewed.
No one much bothers with the smaller versions.
I usually resort to googling the drive model and "HDTach", and hope the person posting the results ran the tests correctly.
---
Fortunately very little you do on your computer is affected by hard drive speed.
Which is why capacity is growing a lot faster than performance.
Facebook
Twitter
Instagram