Also tried to look at copying files locally, and that speed does not seems to be affected......
I'm confused.
The first screenshot provided in a previous posting shows that the Performance monitor selects a vertical scale of 100 Mb/s for the graphical presentation of the network traffic. That 100 Mb/s does not mean that the physical ethernet signalling rate on the wire, the link speed, is 100 Mb/s.
My Win7 64-bit computer has a 1 Gb/s ethernet network interface card. It is currently hooked up to a 100 Mb/s switch. My current link speed is 100 Mb/s, limited by the switch, even though my NIC can do ten times that rate. My Performance Monitor graphs the current network traffic using a 1 Mb/s vertical scale for the graphical presentation while I am typing this, and there is virtually zero network traffic in the sense that the line drawn by the Performance Monitor, rests all the way down on on the floor.
When I start PM (v5), my Performace Monitor network graph immediately shows several peaks reaching all the way to the upper limit (ceiling) of the graph. But at the same time the Performance Monitor reduces the vertical scale on the graph from 1 Mb/s to 10 kb/s (0.01 Mb/s). Thus, the network load when PM starts, maxes out at 10 kb/s and peaks to the ceiling in the graph. After a few seconds, the network traffic drops back to zero while PM is still running. I wait until the peaks on the moving graph leave at the left edge. The Performance Monitor then again increases the vertical scale on the graph to 1 Mb/s. My ethernet signalling rate stays at 100 Mb/s all the time. I would be surprised if application software on your computer actually changes the link speed on your NIC. The fact that your Performance Monitor shows a network load of 500 Mb/s, indicates that you have a 1 Gb/s NIC or better installed, and that you have the link speed to match that.
The second screenshot shows that the Performance Monitor needs a vertical scale of 1 Gb/s for the graphical presentation of the network traffic. Reading the graph from left to right shows network load around 100 Mb/s (1/10th of the 1 Gb/s scale) up to a point indicated by a red arrow and text "PM Close". At that point the network load ramps from approx 100 Mb/s to 500 Mb/s (0.5 Gb/s).
I probably misunderstand something here, but the way I read that second screenshot with the arrow/PM Close marker, network traffic increases about 5 times when PM closes.
Yes, I'm confused.