Sign-in / Sign-up
Your question
Solved

If both ssds and usb flash drives uses NAND flash memory then why the ssds are faster?

Tags:
  • SSD
  • Storage
  • USB Flash
  • Flash Memory
Last response: in Storage
October 21, 2013 10:59:14 PM

here's an interesting question i want to ask,
if ssds and usb flash drives both uses NAND flash memory inside it then why ssds are faster than usb. please explain

More about : ssds usb flash drives nand flash memory ssds faster

a b G Storage
October 21, 2013 11:02:34 PM

SATA cable vs USB port. That's why.
m
0
l
October 21, 2013 11:14:34 PM

It's more than just the port. It's also the controller, the quality of the NAND, and how many NAND packages there are in the SSD compared to the Flash drive. Many SSDs have a large buffer as well, like 256 or 512MB of memory for caching, which also speeds them up tremendously.
m
0
l
Related resources
a b G Storage
October 21, 2013 11:18:28 PM

Still, USB 2.0 ports max speed is like 35 MB/s and USB 3.0 max speed is about 60. So I see that as the limit regardless of what else is in play. And in reality, you don't even hit those speeds.
m
0
l
a b G Storage
October 21, 2013 11:28:20 PM

SSDs are faster because they use better controllers and many parallel chips. They take up more space than would fit on a normal sized flash drive. NAND itself is slow, It has more to do with the size and cost than USB vs SATA. USB3 is fast enough to support external SSDs but you can't make them the size of a flash drive at a reasonable cost. You need a lot of parallel chips to get decent speeds and they just won't fit in that form factor.
m
0
l

Best solution

a b G Storage
October 21, 2013 11:37:14 PM

ksham said:
Still, USB 2.0 ports max speed is like 35 MB/s and USB 3.0 max speed is about 60. So I see that as the limit regardless of what else is in play. And in reality, you don't even hit those speeds.


You're confused. USB2 is 60MB/s (480Mb/s) theoretical and closer to 40-50 in real life. USB3 is 625MB/s(5Gb/s) and around 400MB/s+ in real use. SATA is only 6Gb/s, not 10 times faster. USB3 is plenty fast for SSDs and is the primary way external SSDs are produced.
Share
a b G Storage
October 21, 2013 11:44:01 PM

I did learn something there. Thanks for the clarification @unksol. I did miss a zero, I meant to say 600. Though, I don't get anywhere near those numbers using CrystalDiskMark test on USB 2.0 and 3.0. I know average-wise, I get about 35 MB/s on USB 2.0. And I only have two 3.0 capable drives to test with.
m
0
l
October 22, 2013 12:44:25 AM

Thanks everyone for complete and quick answer, bundle of thanks from my side.
Can someone please explain why can't get the full speed out of usb 2.0, sata and usb 3.0 what are the factors affecting the performance of these interfaces. please explain, thanks
m
0
l