Well, after seeing the post on the Digg.com site I decided to confirm the story. I read a few posts on different forums about the QoS Group Policy setting to reserver 20% of the bandwidth for QoS traffic.
QoS traffic is used by tools such as "net send" and internal windows tools used to discover network presence. Companies that write networking specific software can use the QoS tools to confirm presence of servers, clients, port checking, etc.
Microsoft inserted a Group Policy to reserve 20% of your bandwidth for supporting these QoS packets.
Read Quote directly from the GP editor in Windows XP
Determines the percentage of connection bandwidth that the system can reserve. This value limits the combined bandwidth reservations of all programs running on the system.
By default, the Packet Scheduler limits the system to 20 percent of the bandwidth of a connection, but you can use this setting to override the default.
If you enable this setting, you can use the "Bandwidth limit" box to adjust the amount of bandwidth the system can reserve.
If you disable this setting or do not configure it, the system uses the default value of 20 percent of the connection.
Important: If a bandwidth limit is set for a particular network adapter in the registry, this setting is ignored when configuring that network adapter.
My advice is this:
If your PC is alone on your home network or has one or two PC's connected wirelessly.
If your PC connects to the internet via your cable/DSL router directly.
If you use dialup for your internet access
If you run a small home network with some simple standalone PC's acting as servers.
If you are running Linux/Unix servers and a few Windwos PC's
Set the 20% setting to 0 by following the below procedure.
The only other alternative is you're running a Windows Domain, as I am. If you are running that type of network you should know whether or not you need to reserver 20% of bandwidth for QoS packets.
I myself run a web server and that does not require any QoS tools and/or features, so I tweaked the GP setting. I have read that some VoiP routers and programs are starting to use QoS so you may want to read up on what your specific software uses.
Get back your 20% of bandwidth
1. Go to run and type gpedit.msc
2. Drill down the GP tree following the path Computer Configuration ->Administrative Templates ->Network->QoS Packet Scheduling
3. Under the QoS Packet Scheduling GP look for "Limit reservable bandwidth"
4. Enable it but set it to 0%
Close the GP window and to be safe reboot.
Q. Will this hurt my PC?
A. No, if you have a program or use a tool that utilizes QoS, the packets themselved will be sent out via the TCP/IP stack with the same priority as everything else. This just reserved 20% of the bandwidth so if it had to send out a packet associated with QoS it would use that 20% of reserved bandwidth and get out and back slightly quicker.
Here is the link to the Microsft Tech Net article explaining QoS and why/how to use it.
http://technet2.microsoft.com/WindowsSe ... x?mfr=true
Ack... That was a lot of typing..