[lug] USB3 vs eSATA III question

Zan Lynx zlynx at acm.org
Sun Jul 22 15:16:36 MDT 2018

On 7/22/2018 12:27 PM, Bear Giles wrote:
> I don't think any USB stick is going to be pushing 3 Gbps (but I'm not 
> 100% certain), but perhaps an external hard drive, esp. an external SSD. 
> But is that actually realistic?

I bought one of these Sandisk USB 3 SSDs and it does over 400 MB/s. 
That's 3,200 Mbps.


> In contrast my experience with eSATA is that it really is akin a 
> traditionally installed disk.

Yes. eSATA is nothing special. It's a SATA cable with some extra 
shielding. And I think it's supposed to provide power, but I've never 
used an eSATA drive that relied on it. All of them had their own power 

> Like I said this is mostly from curiosity. I noticed my recent systems 
> haven't had eSATA ports but it's easy to add a half-height card for one. 
> Ditto external drives - they usually only have USB 3 but if you buy an 
> external drive case for your own drive then it's easy to find them with 
> both USB 3 and eSATA. So I have my eSATA gear but it might not be 
> necessary any longer if the quoted USB 3 numbers are accurate.
> Does anyone else have experience with both USB 3 and eSATA?

I had a USB drive enclosure for four SATA drives. It was bad. I blame 
the JMicron controller. It couldn't run the drives inside at anything 
close to full speed even though it should have had plenty of USB bandwidth.

I use eSATA on one of my external backup drives. It performs just the 
same as internal SATA. No difference. But it isn't like a hard drive 
needs 6 Gbps. Only SSDs go that fast.

> (Meanwhile I'm wondering what to do with a few old external drives that 
> are USB 2. They're so much slower and smaller than my external USB 3 
> drives.)

Backup drives don't need to be that fast usually. They'll work just fine 
for backups.

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