Windows 7 file transfer weirdness

[Santilli]

Hi
I've been moving some data between hard drives. They are large, relatively slow SATA drives, and, I'm getting about 95-110 MB/sec file transfer rates, if I transfer one at a time.

I recently tried 5 different file transfers at the same time, and, the transfer rates got REALLY low, like 6-15MB/sec. I was ok with this, thinking that when the first file completed, the large amount of bandwidth it was using, maybe 60 MB/sec, would be transfered to the other files being transfered. NO, they stayed at the same, very slow rates.

I canceled those transfers, and seem to be limited to single file transfers if I want to take full advantage of the drives speed limit. WEIRD. Thought by 7 it would adapt...

 

[ddrueding]

Nope. If you tell it to do a bunch of simultaneous file transfers, it will do what you ask. If you choose a bunch of files at once and copy them somewhere, you have given the OS the choice to do them sequentially, and it will.

Of course, if all your drives were SSDs, you wouldn't have this problem

 

[Stereodude]

You mean seeks slow down STR on a conventional HD? Say it isn't so. oke:

 

[BingBangBop]

Yes, 1 file at a time == sequential and few seeks. 5 files at a time == no sequential data transfer, with lots of seeks. Seeks kill transfer rates. Much better to do the file transfers sequentially than to do them in parallel.

 

[LunarMist]

Hi
I've been moving some data between hard drives. They are large, relatively slow SATA drives, and, I'm getting about 95-110 MB/sec file transfer rates, if I transfer one at a time.

I recently tried 5 different file transfers at the same time, and, the transfer rates got REALLY low, like 6-15MB/sec. I was ok with this, thinking that when the first file completed, the large amount of bandwidth it was using, maybe 60 MB/sec, would be transfered to the other files being transfered. NO, they stayed at the same, very slow rates.

I canceled those transfers, and seem to be limited to single file transfers if I want to take full advantage of the drives speed limit. WEIRD. Thought by 7 it would adapt...

:flower:


Didn't we discuss that limitation when the Barracuda IV came out? Or was it another drive? It is totally normal, BTW.

 

[Santilli]

Nope. If you tell it to do a bunch of simultaneous file transfers, it will do what you ask. If you choose a bunch of files at once and copy them somewhere, you have given the OS the choice to do them sequentially, and it will.

Of course, if all your drives were SSDs, you wouldn't have this problem

7 tells me I do get some REALLY insane file transfer speeds, like 800 MB/sec, copying from the X-25's to the other SSD, and, sometimes they start really high, with smaller files, and slowly slow down to 150 MB/sec.

 

[BingBangBop]

It's called caching.

 

[LunarMist]

It's called caching.

Greg needs to copy 100GB of files and use a timer. The transfer rates will be accurate and probably lower than Winblows calculations.