Our current server has a single Xeon Quad core processor (3.06ghz, 512KB cache)
We also have 8GB of ram.

We've been offered a free upgrade to either of the following

Dual Quad Opteron @2.2GHz
4GB ECC RAM

or

Or 2x Dual-Core Xeon @3GHz
8GB ECC RAM

The server currently hosts a wiki intensive site, with a low traffic forum and a medium traffic forum (Both are Vbulletin forums)

Would there be any benefit of upgrading to either processor options?
The host we're currently using claims we'd get a 10-fold increase in performance by going with the Dual Opteron option, but I'm a bit sceptical.

Any thoughts?
.