Disk is a physical medium with access speed tied to platter speed.
Smaller drives will have slower read/write under the best of circumstances.
(smaller drive = less total surface area speed)
if you compare two drives, both at 7200RPM, the physically larger drive would most likely perform better.
We obviously need to take manufacturer, platter count, etc into account.
But physics is physics, larger drives will be faster at sequential reads.
Now on the other hand, if it's latency that you care about:
Smaller drives have less surface area, which means head seek time is minimized and will more likely be faster to get to the correct data track.
There's a reason enterprise used to use lots of small 10k or 15k disks.
Drives were typically grouped in RAID to add capacity/performance & resiliency.
Smaller drives had less seek time and by using short stroking you could end up with a HDD-based system suitable for database workloads.
en.wikipedia.org
Faster RPM = faster Mbps
physically smaller disk = lower latency
Fun fact, sandisk used to use a figure called 'V-RPM' for their SSDs which gave a rough HDD-RPM equivalent of their SSD series - the average NVME drive would have an equivalent of 25,631,067 RPM.
en.wikipedia.org
