Thats because I know what I'm talking about... I've done the upgrade or so call upgrade myself from x5650 clocked at 4.4ghz and a 5820k
The former cost 65 quid the latter was 600 quid from MM and it was so disappointing for the outlay I sold the 5820k and x99 combo and stuck with the Xeon
If you are in x58 now it's the logical upgrade for very little cost.
The logical upgrade is to wait a few months and get new mobo + cpu. My computer runs fine, why would I spend money needlessly? That's enough for a noctua nhds for goodness sake. Not everyone likes to throw money around simply because they have it.