HDD / Buffering / Network Performance Issues?


Nov 8, 2010
Has anyone ever run into this problem or has anyone found a way to mitigate it?

Let me set up the a scenario.

A file server with Windows 2008 R2 and several hard drives.

All the drives are 5400RPM 2TB drives and formatted standard NTFS.

Copying files between the drives on the server runs at ~100MB/s.

Now, I also have a Windows 7 desktop. And I have a gigabit switch connecting all the computers. Then, a single gigabit connection goes from the switch to the router to bring in internet and route the wireless clients.

The problem I run into, is when I am performing an internal copy from say drive D:\ to drive E:\ for example.

While the file copy is running, when I try to access media from my desktop I cannot stream anything. Video constantly pauses and stutters once a second. I can't even play music. It just constantly skips, just like the video.

It happens when I am trying to stream media that is stored on the same drive that is the source of the internal file copy.

As soon as the file copy on the server is complete of course, the streaming resumes just fine.

This also happens if a third PC starts to copy data from the server via the network. Say another desktop starts to copy data from D:\. This copy process runs just as fast as internal file copy, it runs at about 100MB/s so it does saturate both the HDD and nearly the gigabit connection.

Now If I try to stream media, be it video or even just audio, it constantly skips until the file transfer is complete.

Is there anything that I can do to prevent this?

I used to have problems like this with my WAN bandwidth, seeing that WAN bandwidth is also a limited resource. I was able to resolve this type of issue with QoS completely so I can run things like bit torrent, file uploading and file downloading at full uncapped speeds, while not affecting another user from streaming media, making VoIP calls, browsing, or gaming.

Is there such thing as priority for HDD resource access?

It doesn't really make sense why this is happening, because think back to the skipping audio streaming. If instead of trying to stream the audio, I try to copy it to my desktop instead (while the server is doing its internal copy), the music file copies in a couple seconds to my PC, yet it couldn't stream. If I can copy the file in seconds, why can't it steam which would essentially take ~4 minutes to completely "copy" the song.

I suspect this is a buffering issue? I have tried several media players for both video and audio and they all present the same skipping problem. Perhaps I need to find one with a good adjustable buffer?

Same thing for the movie in that even while the file copy is going and I cannot stream the movie, I can easily copy it in minutes. The copy does go a lot slower when the internal file copy is running, but certainly not 2 hours (which is the length of the movie)

What do you guys think?


Jun 21, 2011
I had a similar problem once and it turned out to be because of shared IRQ lines. Check if your HDD controller and your video card or network card are sharing the same interrupt lines. If so, try changing one or the oher to another line.