Disk to disk copy averaging 162MBps for large file transfer - How is this possible?

tankman1989

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Source drive Samsung SSD - Destination Drive - Seagate 2TB USB 3.0 external.

I copied 35GB in under 4 minutes. This seems incredibly fast to write to an external drive (especially for what the drive cost).

I just did a Crystalmark Benchmark Test of some 1TB SATA III WD black drives and I'm getting about 83-100MBps write speeds and this is all on the same system - a very nice high end workstation/desktop.

Are the speeds that I experienced normal or is something strange happening here. I was wondering if this has anything to do with reading from an SSD vs reading from a standard drive. It seems that write speeds are almost always slower than read speeds unless the files are severely fragmented or the drive is reading a lot of small files out of sequence. I am talking about large file transfers where source and destination are reading and writing in sequence.

Anyone have any idea why I'm getting these speeds?
 
If you are truly USB 3 that is not surprising. After all it is rated for significantly more than 2.0. I recently did some upgrades to some workstations. Basically copying about 6gb from a thumb drive to HP's and Dell's about a year or two in age. Used Microcenter USB 2.0 thumb drives. Time was around 7-10 minutes.
 
If you are truly USB 3 that is not surprising. After all it is rated for significantly more than 2.0. I recently did some upgrades to some workstations. Basically copying about 6gb from a thumb drive to HP's and Dell's about a year or two in age. Used Microcenter USB 2.0 thumb drives. Time was around 7-10 minutes.

Wow, I guess this is correct. I did the transfer again and it was just as fast. I did a test of CrystalDisk benchmark and Samsung disk magician and it was similar. I thought it might have not actually been copying and was just reading or something.

What is really odd is this is copying to a very inexpensive Seagate external (their least expensive external HD line). I also have some WD RAID Edition drives (1TB the Seagate is 2TB) that are SATA III (running on a high end workstation - SATA III as well) and the copy rate is MUCH slower, almost exactly half at 83MBps. I've just never experienced an external out performing an internal like this.
 
Also, keep in mind that higher capacity drives like the 2TB have a higher data density which will read/write more data per rotation than that of smaller drives... perhaps that is adding to the wow factor? :)
 
I just did a test of the drive with Samsung Magician software (comes with their SSD drives) and the read rate was 150MB/s and the write rate is 165MB/s. Now if that isn't confusing IDK what is!
 
***I'm not complaining here, I'm more interested in trying to duplicate this process on other drives and machines I have.

Now I am getting write speeds of 277MB/s which contradicts the speed tests I have done with 3 different programs. This is copying from an SSD to a USB 3 drive as well (reading from SSD and writing to standard external rotational HD). I did a file comparison with the source and destination files and they are exactly the same, so the copy process is working correctly.


To the smart-A that said never heard of Google in the tag line, there is a reason people talk to others and when search results yields conflicting results the only thing that can be done is try it for one's self or ask others. I'd like to know how google is going to answer this type of question. Maybe my search methodology isn't what it should be or I'm unaware of aspects. Last I knew google wasn't AI. What would you have searched to find the answer to this issue or to find out it it was even normal. I'll await your response and you can link to your search results so you can teach me your magical search technique.

My transfer results:
filetransfer.png



Here is a USB 3 speed test results page:
http://www.everythingusb.com/speed.html

desktop-drive-large-file-copy-benchmark.png


I've read maybe 10-15 pages and the fastest write speeds I've found for non SSD drives is about 150MB/s for large file sequential write (which is what I was doing). I don't know where or what to search for when things aren't supposed to be possible.
 
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Geez, just Google it! JK...

Not sure why your getting such a slow rate for the SSD - I run a Samsung 840 PRO and it gets 351 Read and 173 Write in Magician. I run the drive in more or less the "Reliability" mode as opposed to the "Maximum Performance" mode, if that matters. Is your drive aligned?

Maybe pop over to Tom's Hardware here:
http://www.tomshardware.com/charts/hdd-charts-2013/benchmarks,134.html

Looks to be that many of the newer, larger size 2-4TB drives exhibit the same type of speeds you are experiencing (Not the 277MB reading you got there, wowzers!)

Also, what is the drives model # that is in question? Have you had a look at the specs/datasheet for it yet? Is it possible there may be some "cache magic" happening on the drive?

Just a thought here, but I could be talking out my a** - Could it be possible that you wrote the same files to the drive, deleted them, then re-ran the tests copying the same files? Perhaps the drive is intelligently remembering that the file *was* there and is essentially marking the free space (where the files previously resided) back into used space? If so it could simply verify the file at increments and CRC at the end, saving time by not re-transferring the entire file over USB.
 
Geez, just Google it! JK...

Not sure why your getting such a slow rate for the SSD - I run a Samsung 840 PRO and it gets 351 Read and 173 Write in Magician. I run the drive in more or less the "Reliability" mode as opposed to the "Maximum Performance" mode, if that matters. Is your drive aligned?

Maybe pop over to Tom's Hardware here:
http://www.tomshardware.com/charts/hdd-charts-2013/benchmarks,134.html

Looks to be that many of the newer, larger size 2-4TB drives exhibit the same type of speeds you are experiencing (Not the 277MB reading you got there, wowzers!)

Also, what is the drives model # that is in question? Have you had a look at the specs/datasheet for it yet? Is it possible there may be some "cache magic" happening on the drive?

Just a thought here, but I could be talking out my a** - Could it be possible that you wrote the same files to the drive, deleted them, then re-ran the tests copying the same files? Perhaps the drive is intelligently remembering that the file *was* there and is essentially marking the free space (where the files previously resided) back into used space? If so it could simply verify the file at increments and CRC at the end, saving time by not re-transferring the entire file over USB.

These are all new files to the system. Just downloaded to the SSD drive and then copied to the external for storage. I think you and maybe the others are mis-understanding this situation. The thing that is amazing here is the write speed on the external HD. Write speeds are almost always slower than read speeds (except on some SSD's and majorly fragmented HD's) and I just got 277MB/s (which is 3-6x faster than what these drives usually operate at!).

The drive is is a Seagate SRD00F2 - http://www.seagate.com/external-hard-drives/desktop-hard-drives/backup-plus-desk/#specs The data sheet on the page is just about worthless when it comes to operational specs.
 
The new NAS/Media Server I just built myself has 3x USB 3.0 drives that are one part of my backup system.

They backup at a real-world rate of around 1GB per minute, meaning if there is one 4GB file to backup, it completes in right about 4 minutes.

Likewise, if there are 30GB worth of smaller files, it takes around 30 min (sometimes less) to backup.

Pretty cool & I'm very happy! :cool:
 
I think you and maybe the others are mis-understanding this situation. The thing that is amazing here is the write speed on the external HD. Write speeds are almost always slower than read speeds (except on some SSD's and majorly fragmented HD's) and I just got 277MB/s (which is 3-6x faster than what these drives usually operate at!).

Ya, I kind of did go dyslexic on that didn't I, lol.

drjones said:
They backup at a real-world rate of around 1GB per minute, meaning if there is one 4GB file to backup, it completes in right about 4 minutes.

Likewise, if there are 30GB worth of smaller files, it takes around 30 min (sometimes less) to backup.

drjones, that is horrible! 4096MB / 240 seconds = 17MB/s - Are you sure you are hooked up to a USB 3 port on the host? I would expect better speeds from even a USB 2.0 connection.
 
Ya, I kind of did go dyslexic on that didn't I, lol.



drjones, that is horrible! 4096MB / 240 seconds = 17MB/s - Are you sure you are hooked up to a USB 3 port on the host? I would expect better speeds from even a USB 2.0 connection.


Duh....when you put it that way, I guess it doesn't sound so fast, huh? :p

I'll double-check my measurements....it definitely is far faster than USB 2.0, so I must definitely be mistaken. :D
 
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