What determines the speed of an hdd

Aug 10, 2018
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So for example, if I have a 7000 rpm 2.5 inch drive and a 3.5 inch 7000 rpm drive. And for this example they are both the same size From what I've read the 2.5 inch should be faster, due to the density of the files or whatever. But from these forums everyone is saying that the 2.5 inch drive is much slower. Why is that; when they are both running the same speed and the 2.5 inch should have an edge due to the density?
 

mdsimmons1118

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Aug 6, 2018
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The speed is determined by the rotation speed. Generally the mobile 2.5" hdds are slower because a majority of them run 5200 revolutions per minute while the larger desktop 3.5 hdds run at 7200 revolutions per minute. There are even some hdds that run around 10000 revolutions per minute which is even comparable to some of the slower SATA SSDs.
 
Aug 10, 2018
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Yes I get that, that's why I started both drives are the exact same speed. What else effects drive speed because I've read that
2.5 inch drives can be up to 40% slower even if they are the same speed
 

mdsimmons1118

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I assume the 2.5 inch hdd would actually take longer because the write area on the platter is smaller so it needs to run longer for the same area to be written to than a 3.5 hdd. I'm not sure if this is actually the case though.
 
Holly guacamole another atom splitter.

In real life 2.5 slow than 3.5, that's it. The end.

In theory ^what everybody already said.

I will add, EVERYTHING ELSE BEING EQUAL (very important), 2 patters drive faster than 1 platter drive, 'cos 4 heads will can read 4 bits at the same time vs 2 heads, 2 bits.

Assuming single platter, both 2.5 and 3.5 same RPM, 3.5 has edge because per revolution, there is more surface area that passes beneath the rw head, hence can get more data per revolution. Imagine if u could stretch out the circles and make trips out of the patters, the 3.5 strip will be longer.
 

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