Windows 10: USB 3.0 Drive Slowing Down

I'm sorry for the long delay.

USB 3.0 advertises transfer rates of up to 5 Gbps. 60 to 80 Mbps would be about 1% of the advertised speed. Is that accurate?

I've tried a different cable. I know this is important because the USB cable is the only source of power for the hard drive. Unfortunately I can't try a different machine.

Shane.

 

Mooly has mistakenly writen Mbps when he means MBps.

Restriction on speed depends on max reasing speed of source drive, max writing speed of target, types of files (small files vs large files) etc. It takes a finite time to open and close small files, so the total processing time can be a lot more than the actual copying time.

 

USB 3.0 advertises transfer rates of up to 640 MBps. 60 to 80 MBps would be about 10% of the advertised speed. I was originally hoping to get about 50% of their advertised speed. But is 10% the maximum we can expect?

Files are being copied from an internal 7,200 rpm SATA hard drive to an external 5,400 rpm drive. I'm copying my user directory (%UserProfile%). The smallest files are in \Favorites, and the largest are in \Videos.

Shane.

 

Something like that *Smile

I moved a large file today and so took a screen shot. This was to a Seagate HDD (not SSD) USB 3:0 drive. The file size was 17.1 GB and the actual time as measured took 2 mins 43 seconds. So that's 105MB/s actual which compares well with the 109MB/s that Windows showed at the instant I took the image.

 

Robocopy seems to be more efficient when transferring large files. The largest files are in my /Videos folder. The Robocopy log says that the files were copied at 61 MBps.

Someone (Clyde Tilley) posted a comment in a blog post saying that they fixed the problem by disabling Remote Differential Compression. However, Microsoft says not to do this. Do you know anything about this?

Thanks,
Shane.

 

Really? You felt it necessary to denigrate my post based on what experience? How many times have you actually found slow USB transfers in practice?

In >30 years of using/building/repairing computers I've seen hundreds of hard drives slow down as they start to fail.
I've only ever seen two transfer rate problems that were not down to the drive. One was a damaged cable and the other was a new enclosure with a manufacturing defect - but that was slow out of the box and went straight back.

 

Wow, so much misinformation on this thread. Sorry I'm a bit late in replying to this. The first thing to check (after defrag status) when any mechanical (spinning disk) drive starts slowing down is the drive SMART (Self-Monitoring, Analysis and Reporting Technology) attributes. If sectors are starting to go bad, then this manifests itself as slow downs as the drive retries each failing sector multiple times before giving up.

Windows doesn't usually surface any error messages to the user that things are going pear shaped which is why it's up to the user to run diagnostics themselves.

Use a tool like Speed Fan to retrieve the current SMART values for the drive. Look for non zero values under Read/Write Error Rate, Pending Sectors, Reallocated Sector Count and Reported Uncorrectable Errors. A single or couple of errors is survivable. Anything more than a handful and the drive is well on it's way out and should be replaced.

Hard Drives are particularly susceptible to invisble damage from knocks and drops. Reading off the SMART values is sometimes the only way to ascertain for sure if things are heading south.

Be aware that basic USB to SATA interfaces used by some drive enclosures don't support reading SMART data. In this case you'd have to remove the drive from the enclosure and connect it another way to a working machine to retrieve the attribute values. Your local reputable computer shop may be able to help if this is beyond your capabilities.

Also, 2.5" mechanical drives as used in most portable drives top out at around ~120MB/s. Modern 3.5" drives can hit around 220MB/s peak/sustained with large files. Note, that's MB (Megabytes) per second. It's the unit of measurement for drive surface to/from read/write head transfer speeds - sometimes referred to as the media transfer rate.

The USB interface speed on the other hand is measured in Mb/s (Megabits per second) or Gb/s (Gigabits per second). There are a thousand Megabits in a Gigabit. And there are 8 bits in a byte, so divide Mb/s by 8 to get the rate in MB/s.

480Mbps is the max theoretical transfer rate for USB2.0 and 5Gbps for USB3.0

For large transfers, the whole transfer can only go as fast as the slowest part of the train, for USB3.0 this is always the media transfer rate - i.e. 120MB/s for a cutting edge 2.5" drive.

 

Hi,

True but why add to it ?

Slow USB transfers aren't pertinent to HDD, SSDs or any other media really, fixed or removable.
Sure enough, damaged media support isn't going to speed things up but that's only one small aspect of the story really.
SMART data may be absolutely fine and you can still experience sluggish USB transfers.

Cheers, *Wink