Usb Upload/download Discrepancy

is there some inherent reason these transfers would occur at different rates? i copied like 40G from a 64G stick to a laptop in around 45 mins; when i later tried to copy the EXACT SAME 40G in the other direction (had deleted/made space in meantime), it took 6+ hours!

and another thing -- tried copying a 4.3G file (movie) to said stick when there was about 7G remaining, and it said "not enough space". what thu...?? does 4.3G really take up more than 7G somehow, or does USB just not like LARGE CHUNKS? (i later copied 4.3G worth of other, smaller, stuff into the space just fine!)

 

You stumbled on your own answer "does USB just not like LARGE CHUNKS?" It has to do with the format of the USB, FAT32 has a 4GB limit, you need to format it NTFS or ExFAT to copy large files.
Most devices have different read / write speeds:
USB 2.0:
Sequential read speed range = 10~25 MB/s
Sequential write speed range = 3~10 MB/s

USB 3.0:
Sequential read speed range = 60~150 MB/s
Sequential write speed range = 10~45 MB/s

 

thanks on both points.

i don't wanna mess w formatting when this is the only file so affected. i'll just DL from scratch on the new PC.

was not aware of the read/write discrepancy. i guess that 6:1 ratio there is what i am seeing.

have to transfer 800G or so. gonna be a loooong night...

 

The other thing is use robocopy when copying data like that, it seems faster than Windows explorer transfer, or Teracopy is a good program for that too.
Also you can split large files into smaller ones so they will fit the requirements of the drive. I recall HJSplit was a good one, also 7zip (How to)