I use an USB keyboard and mouse (Microsoft Wireless Keyboard 1000) and if I connect my PC to internet via an ethernet cable in one of the 2 Gigabit port Intel 82574L (using PLC : power line communication) on my ASUS P6X58 WS and download something, I can't use my keyboard as usual : letters appear after hitting the key 2 or 3 times. It seems the fact of downloading makes the keyboard lags (and the mouse but a bit less). Keyboard and mouse lag less when I don't download anything.
If I use a wireless connection with PCI-e or USB WIFI key, no problem.
As soon as download stops, it's a bit better and if I unplugged ethernet cable, everything fine.
I'm under Windows 7 x64 Ultimate, drivers version of Intel(R) 82574L Gigabit Network Wonnection : 18.104.22.168.
How to solve it please ? Are there any settings to avoid this behaviour ?