SSD vs. HDD – Speed Comparison of External SSD and Internal HD

external hard drivehard drivessdusb

I am using a laptop for gaming because I am not able to build a desktop currently. I was thinking about getting an external SSD for the speed, but I was wondering if it would be worth it, as I am not sure if an external SSD through USB 3.0 would be faster than the internal HD. Does anyone know if the external SSD would be faster? I'm thinking in general, not for a specific HD/SSD comparison.
Also, I did look at the other question posted below, but they were talking about booting an operating system, while I am looking at storing games and programs that I will be using. As I understand it, USB 3.0 may not be as great for the sustained usage I would assume gaming would require.
internal mechanical drive vs external SSD

Edit: Here I am looking at an actual USB SSD drive rather than a SATA SSD in a USB enclosure. For example, a MyPassport or similar SSD external mass storage device. However, many of the points in the current answers are still valid. Thanks everyone.

Best Answer

In theory it would not work:

  • Internal SATA speed is likely to be 6 Gbps, and USB 3.0 is slower than that.
  • external USB enclosure is likely to introduce further delays (SATA to USB, then USB to memory) as well as limiting protocol capabilities (e.g. by default the USB drive won't have write back cache, what Windows calls optimize for speed, but write through or optimize for fast removal. At a lower level you lose SMART and, I think, write queue optimization).

In practice, you might get better performance in sustained reads, when the SSD overtakes the mechanical disk cache capability. The mechanic is not always capable of keeping up with the SATA interface, and 6 Gbps is only the maximum talking speed between electronics: the platter may have been left behind.

Run a disk read speed test with large data blocks and see. Values below 4-5 Gbps might indicate a SSD would do better.

On the other hand this is only true if your game does read lots of sequential data. Random reads are probably best left to the internal disk.

Related Question