How to change network speed in Windows Server 2003 & Windows XP?

Question

Windows

The domain is headed by 2 servers running Windows Server 2003 . The network has more than 50 workstations running Windows XP SP3. Also raid is connected to the server. The essence of the problem: when information is copied to raid, the server limits the data transfer channel to 20% (gigabit network).
When connecting more than 4 clients, the speed is divided equally among all. How to make it so that when 1 client connects, he gets access to the entire channel?

Answer 1

configure the QoS (Quality of Service) service

Answer 2

Let's try with numbers, shall we?
1. When copying "from the server to the raid", what is the write speed to the "raid"?
2. When copying from a client to a server, what is the network load on the client and server?
3. When copying from a client to a server, what is the load on the disk subsystem on the server and client (write and read speed).
How we measure: run perfmon on the client and server, select the necessary counters (read / write counters per second to a physical disk, network to an interface), run a large file for copying, just a large file, a movie, for example, look at what happened on the counters, the result here. During the test, there should be no other load or it should be minimal.
Without this data, there will be no answers, but guesswork on the coffee grounds. Fast-slow and half-quarter is not an indicator.