How is a "portable" SSD a great thing?

Hi, I've recently been noticing alot of "portable" SSD drives that connect via USB. (USB 3.1 I think is what I saw though I'm not sure that that is the minimum port requirement...)

From what I understand about hard drives though, I always thought that they were limited by the port to which they are connected. So.... given that SSDs are supposedly blazingly fast (at least when connected internally via SATA or .M2), how is an SSD capable of being blazing fast and therefore a worthwhile investment when it is a "portable" one connected via USB?

orlando1974 said:

how is an SSD capable of being blazing fast and therefore a worthwhile investment when it is a "portable" one connected via USB?

"Blazing"...........compared to what?

What are the alternatives in most situations? A thumb drive? A spinning drive that may require a power source other than a USB port?

I don't use an external SSD connected to a USB port, but I might buy one of those 10 dollar cable adapters so I can use an ordinary "internal" SSD rather than a thumb drive in the same port.

Cliff S said:

Depends on if the External SSD uses USB 3.1 gen 2, or Thunderbolt.
USB uses SATA protocol, and thunderbolt uses PCIe
From Samsung:

The T5
INTERFACE
Compatible with USB 3.1 Gen2 (10Gbps), backwards compatible

TRANSFER SPEED2)
Up to 540 MB/sec.
------------------------------------------------------
The X5
INTERFACE
Thunderbolt™ 3 (40Gbps)

SEQUENTIAL READ
Up to 2,800 MB/s

Thanks for this.
2 questions:

1. First one says backwards compatible. So if I have only a USB 3.0 port on my laptop, it will still work but.... I won't get the 540MB/sec speed? If that's the case, then in my situation it may not be worthwhile correct? (unless of course I get the cheap adapter referred to above)

2. Why is the first one measured in Transfer Speed, while the second is measured in Sequential Read? Or is it the 40Gbps spec, which is constant as it will always and only be using the Thunderbolt 3 port?

Hi folks
use USB3-->SATA type adapter == works really well -- often have VM's on external SSD's.

There's more to this question than RAW speed -- if it's an application e.g a VM you are running from the SSD a lot of the I/O can be "buffered" and Pre-fetched so you aren't waiting on data transfer from the USB3 port. Windows actually has a very sophisticated "pre-fetch" algorithm which based on your use it attemps]ts to "guess" what I/O you will need next and while the computer is say busy with a CPU bound process the I/O controller will read the data into memory - so when you want to use it it's there ready.

Also SSD's are inherently faster than USB thumb drives and are far more robust -- thumb drives don't have a very long "duty cycle" if they are used continuously.

I also get very good response using an SSD via USB3 adpter as a Windows to Go device - almost as fast as the internal HDD (SSD).

I/O behaviour in a complex OS like Windows is far more than the basic RAW data XFER rate.

Sorry for the geekish stuff but that's essentially how it works.

Cheers
jimbo

Cliff S said:

1. Correct, the speeds will be slower. An external SSD is only worthwhile if you do a lot of writes, for reading, you won't really notice a difference, specially if the files are often read(like music) as windows with cache them anyhow.

The use is mainly to read large sample libraries (in the context of music studio). Sounds need to be accessed very quickly in real-time.

f14tomcat said:

What $10 adapter is that? Love to hear about it.

I don't own one, but my understanding is that this would do the trick; required power comes from the USB port:

Amazon.com: USB 3.0 to SATA III Adapter Cable with UASP SATA to USB Converter for 2.5 Accessories