Windows 7 Forums
Welcome to Windows 7 Forums. Our forum is dedicated to helping you find support and solutions for any problems regarding your Windows 7 PC be it Dell, HP, Acer, Asus or a custom build. We also provide an extensive Windows 7 tutorial section that covers a wide range of tips and tricks.

Windows 7: LAN Network File Copying - Some Files FAST; Some Files SLOW. Why?

22 Sep 2018   #1

Windows 7 Ultimate x64
LAN Network File Copying - Some Files FAST; Some Files SLOW. Why?

I have a Gigabit network and for most files i get 100+ MB/s speeds when copying to/from another networked Windows 7 x64 PC. However, there are some specific files (of equivalent sizes as the faster ones == 1-3 GB) which refuse to go faster than 50-59MB/s both ways.

I first thought it could be that the PC's HDD's were heavily fragmented so i defragged both. That didn't help at all.

I noticed that the one HDD uses 4KB cluster sizes, while the other one uses 64KB. Not sure if that could be the possible problem? But how could it if other files are able to achieve 100+MB speeds with no problems.

I cleared the system memory file cache (via RAMMap) to ensure there was no cheating in speed transfers.

I also tried copying the slow files from HDD to the remote PC's SSD. That didn't make a difference either; same slower speeds.

Both PC's are connected to a gigabit switch. Jumbo Frames are disabled. Both NIC cards are set to 1Gbps Full Duplex instead of Auto Negotiate. Flow Controls are turned off.

Is it possible these slower files could have a certain byte size that isn't efficiently aligned in an 8-byte format which Windows might be preferring and could be slowing transfers? Not sure if that makes sense to anyone. When coding, things like this tends to come up when looking for performance, so not sure if the same thing might apply here.

I didn't turn off auto tuning because as I already mentioned most files are getting 100+MB/s speeds so it doesnt look like an auto-tuning issue.

Oh and i dont have any anti-virus nor firewall (e.g. Windows Firewall) enabled on either machine.

And lastly, "Large Send Offset (IPv4)/(IPv6)" is still Enabled (for both NICs) because when i disabled they slowed everything down to a max of 84MB/s or less.

I'm using new cat6 cables but i decided to switch to cat5e for another test and the speeds were the same.

Both NIC cards have their latest drivers.

Unfortunately, i don't have a 3rd PC that has gigabit..the rest are 10/100, so i can't see if the slow speed happens across a different PC beyond these two.

My System SpecsSystem Spec
22 Sep 2018   #2

win 8 32 bit

Welcome to the forum. How are you coping files ie explorer you often find built in robocopy is the best as it was written for servers. It's hard to work out speed as so many things can effect it. Often anti virus will slow it as it can scan on read and write robocopy tends to get past that being CMD you can now get a free GUI for it now
My System SpecsSystem Spec
22 Sep 2018   #3

Windows 7 Ultimate x64

Thanks for the reply. I am simply drag/dropping the files from one window to the other.

As mentioned, most files get the 1Gbps speeds (100+ MB/s) but only some very specific files are stuck at always 50MB/s. So i doubt robocopy will help since most files aren't affected -- it's clearly some other issue.

As mentioned i dont have any anti-virus nor firewall running on either machine.
My System SpecsSystem Spec

22 Sep 2018   #4

win 8 32 bit

Are they a specific type of file? try the robocopy gui as its specificly written by MS to do this job
My System SpecsSystem Spec

 LAN Network File Copying - Some Files FAST; Some Files SLOW. Why?

Thread Tools

Similar help and support threads
Thread Forum
Why does copying files start fast then slow down so dramatically?
I have a lot of files to move, about 1200GBs to go... The files are more or less all the same size, about 10MBs each. They are being copied from one external HDD to another, via USB3.0 and my Win7 x64 PC. There are a number of external USB drives involved and they all do roughly the same thing....
Hardware & Devices
Slow file copying from Win 7 PC to other network PCs
I have a modest home network with two Windows 7 PCs and one Windows XP PC connected via a D-Link DIR-655 router. The XP machine and one of the 7 machines are connected to the router via gigabit ethernet ports, and the other PC by a wifi card. Internet download/upload speeds on the two wired...
Network & Sharing
Copying files to discs (live file system) is EXTREMELY slow
I've been burning discs using the Windows 7 built in burner using the Live File System option, but when I drag and drop files to DVDs and the copying files window comes up, it's extremely slow. Like 1.29mb-2.49mb per/sec slow. Any ideas? This can't be normal, it takes a LONG time to for the files...
General Discussion
Copying files seems slow
I am currently backing up files in preparation for my new hardware. I am copying file from a samsung F1 1Tb drive to another identical drive. I thought that these drives were fast, capable of around 40mb/s but atm the process is only managing 19mb/s.
Hardware & Devices
Slow speeds copying files locally on a network drive
I set up a network folder on one of my computers and I use another computer on the network to manage the files on it. It all works fine until I try to copy a file or folder from one location on the network drive to another location on the same network drive. Instead of copying the file locally, the...
Network & Sharing

Our Sites

Site Links

About Us

Find Us

Windows 7 Forums is an independent web site and has not been authorized, sponsored, or otherwise approved by Microsoft Corporation. "Windows 7" and related materials are trademarks of Microsoft Corp.

Designer Media Ltd

All times are GMT -5. The time now is 01:18.
Twitter Facebook Google+