Hello!

I have read specification about two Intel Sandy Bridge E Core i7 processors:

a) 3960X (L3 15 MB cache, 3,3 Ghz, 3,9 Ghz in Turbo Boost) - 900 $
and
b) 3930K (L3 12 MB cache, 3,2 Ghz, 3,8 Ghz in Turbo Boost) - 500 $

Two differences between these two processors a
- 0,1 Ghz difference
- 3 MB L3 cache difference

I heard unofficial prices of these two processors and the difference is
nearly half.

Questions to you:
1) Why will a) processor be so expensive?
2) Is 0,1 Ghz and 3 MB cache better worth price?
3) Will video rendering in Sony Vegas Pro be extremely better in the
comparision
to b) processor?
4) So, will a) processor be worth buying? Will it be better to save nearly
400 $
and have only little worse processor b)?
5) Maybe there is some invisible parameter which makes the a) processor so
extreme
as it used to be call, and maybe it is so extreme if we look at working
efficiency?

Thank you in advnace
Netm.