Processor upgrade

I don't know exactly where to post this topic, but I think it would best be placed here.

I'm currently looking to upgrade my processor, I'm looking at both the AMD Phenom II x4 965 and the AMD Phenom II x6 1090T.

They both take up 125W of power and the six core is just $40 more than the four core. And I have a few questions:

1) I have a GTS 450 GPU and a 500W power unit (specifics are in my specs below), and I'm wondering if my power supply can hold up to the demand on one or both of these processors (I have also noticed a 95W quad core at 3.0GHz and a 95W six core at 2.6Ghz and am now wondering if either of those would be a better idea).

2) Is the extra $40 worth it to go six cores instead of four cores?

3: After seeing benchmarks I've seen that the four-core is faster than the six core, but will the extra two cores actually boost performance in heavy processor-demanding games?

Thank you for any advice in advance.

If it is a good high end power supply which judging by your specs it's a fair one at least.
I think you will be okay.
The high-mid to high range psu's are often rated under what their actual delivery potential is.
I have a 1000 watt that can kick up to 1200@84amps if it needs too, so yeah majorly overpowered.

Oh that's something to note too, strong amps are a key component too.

If wattage is the amount amps is the force at which it's applied.
so 500 watts with very small amps is far less useful than a 500 watt with a strong amp rating.

So you are saying it would be a good idea to up my Power supply to one is more amperage?

EDIT:
I checked http://www.extreme.outervision.com/PSUEngine

It says I should be good with the 125W processors, it says my system as a whole would only use 337W max out of the 500W my power unit produces. but I am not sure if the output of Amps on my unit is sufficient enough.

Amperage readings:
+3.3V = 22A
+5V = 25A
+12V (1) and +12V (2) = 18A

Actually that should be sufficient to do what you want.
It never hurts to have a wattage/amperage slightly above what you actually need is all I'm saying.
I'm proof of that I'm on a 1000watt psu ... which admittedly is overkill for any system, but you can get 750 watt psu's that aren't that pricey and it'll power anything you ever do to that system.

Well apps such as video converters and certain rendering apps will use all the cores.
The majority of stuff will only be using 4 or even 2 depending though.

Well, looking at this, I'll look at getting the Seasonic X750 Gold or Corsair Professional Series HX750, then get a 6-core 1090, a lot of things in the future should utilize all cores, and I think it would be best to skip the cost of a 4-core and just go straight to 6-cores.

Yeah, given the minimal price increase for 2 more cores there's really no reason not to get it.
Of course anyone that's been in this as long as I have (started at about 8 years old am 37 on the 1st)
There really is no such thing as future proof. You just do the best you can at the time.