I would like to mention an application that I found a year or so ago, and I have found it to be invaluable. I have used it on XP though Windows 8, and currently use it on ALL of my computers.
The program is called NetWorx, a bandwidth monitor. In all of my testing, it works in harmony with all of my applications, is add free, malware free, spyware free, and heck, its just FREE. I recommend that you check it out and I am sure it will serve you well.
I started using it when my ISP began to throttle usage on a monthly basis, and I needed to monitor my usage. This NetWorx does the job, and does it damn well. It is extremely configurable, and you can break down usage on any or all NICs, combined or separate, your router and all traffic combined, or each node separately. You can get hourly, daily, weekly, monthly or annual usage, as well as live stats with graphs. Basically what ever you want. And it just sits quietly doings it job.
(No, I am not affiliated with SoftPerfect, I just am very impressed with the program. It has filled a need that I had, and does it well).
I have also used the gadget mentioned in the above post, and it works well, but NetWorx works much better for my needs.
http://www.softperfect.com/products/networx/
Pete