On Thu, 2022-08-04 at 17:40 -0400, Stephen Partington via PLUG-discuss wrote:
> 
> 
> On Thu, Aug 4, 2022, 5:33 PM Steve Litt via PLUG-discuss <
> plug-discuss@lists.phxlinux.org> wrote:
> 
> > On Thu, 2022-08-04 at 05:43 -0700, Keith Smith via PLUG-discuss wrote:
> > > 
> > > 
> > > I'm thinking the bottleneck might be the USB.  Any thoughts PLUG?
> > 
> > I'm almost positive that a USB2 interface will badly bottleneck an SSD.
> > Might as
> > well get a 5400rpm spinning rust.
> > 
> > If you have even one USB3 on your computer, you can get a USB3 USB hub
> > with its own
> > power supply, so you have plenty of USB3 ports.
> > 
> > SteveT

> An ssd on usb 2 still has an advantage in random seek operation and power
> consumption vs spinning rust. On top of being vibration and movement
> resilient in comparison. And it will also provide a touch of
> future-proofing.

A USB interface maxes out at 53MbYtes/second.
See https://en.wikipedia.org/wiki/USB#USB_2.0 .

The read/write speed of a 5400 is somewhere between 75MbYtes/second and
150MbYtes/second --- everyone has a different figure. See
https://datarecovery.com/rd/does-hard-drive-rpm-affect-lifespan/ . Nobody broke it
out into read speed and write speed --- everyone just quoted a read/write speed.

So the USB2 connection cannot deliver the 5400's output. It retards the speed of the
5400 spinning rust. So *obviously* it would retard the speed of the SSD. All the
random seek advantages in the world mean nothing if it bottlenecks at the USB
connection. 

Vibration and movement resilience of spinning rust can be maximized with a 2.5" form
factor, and a 5400rpm 2.5" doesn't use much power or shed much heat. A decent
5400/2.5.

As far as future proofing, here's a 5400/2.5 for $43.00:
https://www.newegg.com/toshiba-mq04abf100-1tb/p/1Z4-00HU-00017

For the $110.00 required to buy 1TB SSD today, three years from now that sum will
probably buy you 4TB. The best future proofing you can do is buy it cheap and save
for when SSD will actually benefit you.

With a USB2 interface, SSD will perform as slowly as 5400. So I stick by my initial
statement, if USB2 is the only possible interface, he's might as well get a 5400rpm
spinning rust.

SteveT
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