New Build Network problems?!

Note: This has happened a few times so far.

1) I install a fresh copy of windows 7 on the formatted hard drive
2) I get 30MBPS download (I pay for 30 so this is what I want) for the first boot
3) I re-boot, maybe install a driver or two for the graphics card or USB Mouse/keyboard
4) Network speed drops to 13-16 mbps and is jumpy and unstable
5) After an hour or so speed drops to 2 mbps, sometimes dipping to 100kbps and even disconnecting fully and randomly

Specs:
i5 2500k
z68ap-d3
HD 6850
2*4GB Kingston HyperX 1600mhz LP
Corsair Builder CX 600W
Razer Deathadder (1800DPI edition)
Razer Lycosa

The USB slots are also unstable aswell if that's relevant - they seem to randomly lose power for short periods of time making my mouse jump and miss keys while typing.


Really annoying me, feeling like I can't properly use my new build!
Any help appreciated.

I have tried this with both a WN111v2 USB wireless N dongle and a 150MBPS Addon pci-e adaptor, both get same problems..

Sounds like either your motherboard or PSU are at fault. Do you have another power-supply you can swap out to test?

Also did you mean 30 Mbps and not 30 MBps? Have you installed your chipset drivers for your motherboard?