Does 25 mg of L3 Cache Make a Big Difference over 15 mg?

Trying to upgrade my Asus Z9PA-D8 motherboard with either Dual Xeon 2687W V2 ES 3.4Ghz 6 Core 15MB or Dual E5-2667 V2 CPU with 8 core and 25 mg of cache. 

Price point the 2687W V2 ES 3.4Ghz 6 Core 15MB are only $216 used and the E5-2667 V2 3.3Ghz with 8 core is $485 used.

If I REALLY need more than 8 core but the 12 cores is just fine, then will the one with 15 mg of cache do the job?  If I need 25 mg then I'll "bite the bullet" and pay another $500 for another E5-2667.

Now I COULD get just 1 of the E5-2667 V2 CPU with 8 core and see how it goes, but I know Adobe Premier recommended dual Xeon with 12 core so Hmmmm...

Both turbo at 4.0 and the and their clock speed is only a 0.1 difference.

I also will be using After Effects so that is to be considered as well.

If anyone could help me with this decision I would really appreciate it.

Also any other tips on processors over the ones I just mentioned? I'm also running 32 gigs of RAM and if I need 64 please let me know as well.

Thanks!

James