[Buckshee Rounds]

I've been looking online to get a general idea of what speeds I should be getting and let's just say I feel I'm being sold short. I have a 32GB flash drive connected to a 2.0 port. This was not a cheap drive so it should be fairly decent. I'm finding the transfer speed rarely goes beyond the 4-6MB/s range and this is with a freshly formatted stick too. The stick is formatted in FAT32. I've tried turning on write-caching, but it won't let me do it for this stick.

What kind of speeds should I realistically be getting with this thing? At 4MB a sec I might as well be transferring data by writing it on frigging paper.

[Alan Bolte]

USB 2.0 hard drives should get you something in the 25-30 MB/s range for sequential writes - I'm not really familiar with flash but I'd think you'd get similar results.

Could you be more specific about what happens/why you can't enable write caching? Are you logged in as an administrator?

How are you measuring the transfer rate? If it's showing up as a drive letter you can use a simple free benchmarking tool like Crystal Disk Mark to measure the performance for different types of operations. One thing I've found is that a lot of mid-range storage devices that advertise great speeds may have the advertised sequential write rate, but have fairly poor random I/O performance.

[Klaustrophobia]

flash drives are usually much slower than external hard drives.  4-6 doesn't sound too unreasonable for a 2.0 flash drive.  10 is a very good one.  my USB 3.0 flash drive only does 25-30, compared to up to 180 for my crappy 3.0 external hard drive.

[Nuke]

i think you are limited by the flash chips more than the usb transfer speeds. 2.0 is pretty fast (480 Mbit signaling rate, 280 Mbit or 35MB/sec effective transfer). they do sell higher speed chips, and you can get sd cards and thumb drives that have a faster transfer rates than others.

[Buckshee Rounds]

USB 2.0 hard drives should get you something in the 25-30 MB/s range for sequential writes - I'm not really familiar with flash but I'd think you'd get similar results.

Could you be more specific about what happens/why you can't enable write caching? Are you logged in as an administrator?

How are you measuring the transfer rate? If it's showing up as a drive letter you can use a simple free benchmarking tool like Crystal Disk Mark to measure the performance for different types of operations. One thing I've found is that a lot of mid-range storage devices that advertise great speeds may have the advertised sequential write rate, but have fairly poor random I/O performance.

I'm not really measuring the transfer rate, I'm just observing what the transfer speed is in the 'copying files' window. This is on win 7 64 btw.

When I tried to enable write-caching I went into the stick's properties then went to 'Hardware', clicked on the device I wanted in the list and hit 'properties', then went under 'policies'. When I had the removal policy set to default (ie. Quick removal) it would transfer files at around 4-5 MB/s (both onto and off the drive). If I hit 'better performance' I can tick the box for 'enable write-caching', but once I hit OK it tells me I can't enable write-caching for the device. Now this is where things get weird: if I still have the removal policy set to 'better performance' then copy files onto the drive, it'll start out at 100MB/s then gradually slow down all the way to 4MB/s over the course of 5 minutes or so.

This is what is frustrating me. The drive is clearly capable of faster speeds, but for whatever reason it won't maintain such speeds. I can actually take advantage of this: instead of transferring a big load of data (like 7GB odd) it's actually faster to transfer one file at a time because of the 'speed boost' at the start of each transfer. I swear I'm not making this up.

I hope I've explained that clearly enough, because it is very strange behaviour. I'm a total layman with techy things so you have to bear with me here.

EDIT: Just a note that the '100MB/s' figure is conservative, I've seen it stated at 128MB/s at its highest.
EDIT2: Meant to add this is a 3.0 port not a 2.0, my mistake

[Fury]

I have 32GB Transcend JetFlash 600 which states in tech specs that it is capable of writing 16 Mbytes (MB) per second. I used robocopy to transfer three 700MB files into the stick, average writing speed was 12,82983333333333 Mbytes (MB) per second, in other words reasonably close to promised write speed. However, Windows file transfer dialog shows about 60-70 Megabytes (MB) per second, which is huge discrepancy. This was without write caching.

I also compared these results to my 2GB Kingston DataTraveler. I couldn't find definite official specs for this old model, but robocopy gave me 1,551133333333333 Mbyte (MB) per second. This time around Windows file transfer dialog gave me more or less same as robocopy.

As you have 32GB stick, you should format it as NTFS. With FAT32 you can never put files over 2GB on it. As for what speeds you should be getting with your flash drive, consult tech specs provided by its manufacturer.

As for 100 MB/sec or over, you won't be seeing those kind of transfer speeds unless your flash drive is top-end USB 3.0 flash drive. You might actually find a review of the drive or few by googling.

[FreeSpaceFreak]

EDIT2: Meant to add this is a 3.0 port not a 2.0, my mistake

Just connecting it to a USB 3.0 port isn't enough for great speeds - the stick itself should be 3.0-capable as well. And even then, there can be a big performance difference between different models.

[Nuke]

flash just doest write that fast. the only reason ssds can do the high transfer rates is because it writes to a bunch of chips in parallel. when you are dealing with a cheap stick, its usually just a single chip flash and mcu under an epoxy blob.

[jr2]

http://en.wikipedia.org/wiki/Secure_Digital#Speed_class_rating

I've seen SD cards rated up to 30 MB/sec IIRC, but those were the top notch ones.  If you get a flash chip that doesn't tell you it's speed class or tranfser rate, take a guess that it's not that great.  If you still want to check, google the model number and specifications, e.g., search

Code: [Select]

CMFSS3-128GB specifications
If you still can't get a definite answer on the transfer rate, stay away!

http://en.wikipedia.org/wiki/Secure_Digital#Comparison_to_other_flash_memory_formats

As you can see from the chart, SD cards are rated at a max of 832 Megabits (104 Megabytes) per second, not sure if that's approaching the max for flash memory, or if perhaps more than one chip is used to achieve that rate (I would assume so).

[Alan Bolte]

Well, this has been an education. I've never really worked with flash in that kind of detail before.

Also, I don't generally trust Windows displayed transfer speeds, although Server 2012 might change my mind on that.

[Nuke]

im almost certain they broke something back with vista, because thats when copy speeds went to hell. i dont think they ever fixed it.

[jr2]

* jr2 concurs