For the "Why so high" question, Windows 7 has a WEI score that tops at 7.9.
For the CPU see if you can put a bit more out and get this:http://www.newegg.com/Product/Product.aspx?Item=N82E16819115207
$149 + free shipping. A E8400 wouldn't be that bad but a quad core would be better for the long term.
THE FSB (Front Side Bus) works by taking the BCLK (Base Clock) and multiplying it by the multiplier of the CPU to get the CPU clock speed. The Q8300 has a FSB of 1333MHz total. Its BCLK is 333MHz quad fired which = 1333MHz. So the multiplier is 7.5 x 333MHz which equald 2.5GHz. The multiplier can also downclock to 6 which would mean 2GHz for low process power applications via SpeedStep.
The FSB also links the CPU to the memory at the same speed but works a bit differently. It will run a 1333MHz but is really 667MHz in 2 channels which equals 1333MHz. Each channel of memory runs at 2x the BCLK. So 333MHz x2 means each channel of memory is running at 667MHz and then, again, is multiplied by 2 since each channel is running at the same speed giving an effective speed of 1333MHz.
A bit weird but it works out in the end.