are you saying not worth the upgrade?
Good question! It depends.
The vast majority of software out there primarily benefits from a faster clock and won't see a much of benefit, if at all, when you jump from 4 to 6 cores. This is not true of ALL software mind you, but most. So most likely it's not worth it unless you are using some very specific software that scales well with more cores.
If I make the assumption that you are using typical software that would benefit far more from a faster clock speed, you would be better off finding a faster quad core. An X3580 for example is a 3.33GHz quad core and goes for around £60. The 25% increase in clock speed should translate fairly well into real-life noticeable gain.
On the other hand, if you are primarily using one of the very few applications out there that
does scale well with more cores, then yes, the X5650 at the same clock with 2 more cores is the better bet. "Handbrake" for example will use every single core you can throw at it, and it scales perfectly--if you went from 4 to 6 cores, you'd have almost exactly a 50% speed increase to match the 50% more cores. Of course, all the
other software you use will see little to no benefit at all.
For RAM, the story is exactly the opposite--you want more, not faster. I wouldn't pay to change your RAM from 1066 to 1333--that is not a noticeable speed difference in real life use. You would be FAR, FAR better off using the money to buy additional RAM, especially since you only have 4GB.
