q9650 worth the $600?

YES.
The q9650 has SSE4 and is quad core.
This will be more important once more software gets written for multi-cores. DX11 will also better handle multi-cores.
The q9650 will easily outperform the e6700 on multi-thread apps (like h.264 main concept).
The 775 socket will be dead soon anyway. So the you can keep your PC the way it is for the next few years.
If you don't notice any performance problems, then just save your money.
I'll personally get the q9450 then OC to 3 ghz.

Worth is relative. When you are purchasing a Q9650, you are first off paying for the highest stock clocked mainstream quad core. Which gets you the highest multiplier. On average they will overclock the highest (I said on average, there are exceptions to the rule). They don't usually represent the highest value though. This is because the percentage that they can overclock is lower than some of the lower binned parts.

The formula for this is:

(OC - Stock)/Stock= Y
Y X 100 = % of increase of clock over stock

For example lets say a given Q9400 can be overclocked to 3.2GHz from it's stock of 2.66GHz

(3.2-2.66)/2.66=0.203
So it overclocked 20.3% above stock (being conservative)

Now your Q9650 lets say overclocked to 3.54GHz from it's stock 3.0GHz. Now it's overclocked by the same absolute value, but:

(3.54-3.0)/3.0=.18
So it only overclocked 18% over stock.

Now using these same numbers to calculate value is easy, especially with CPU's from the same family as their speed tends to scale linearly with clockspeed.

Q9400
3.2GHz/$315= 10.2MHz/$

Q9650
3.54GHz/$600= 5.9MHz/$

Pretty easy to see.

Now I just pulled these numbers out of thin air, as I'm sure both CPU's could overclock much higher. The point I was trying to make was the percentage gained from the higher binned parts is usually lower than the lower binned parts. Now it depends which is more valuable to you, the absolute highest clock, or the percentage of value added (which you didn't pay for) from overclocking. So from this illustration it would be fairly simple to overclock a Q9400 up to or past that of a stock Q9650 without laying down that $600 dollars. Now if you have to have the absolute highest overclock or you are going stock but want the highest binned part, then the Q9650 is what you would consider the most valuable. Otherwise go with a lower binned part if you must upgrade, and get more MHz/$.

Also by gambling on a lower binned part, you just may get lucky and get one of those legendary oveclocking CPU's. I have never met a C2(D)(Q) that wouldn't give an additional 33% or higher with decent cooling.

It'll be fairly significant. I'd go for the 9550 though - only a tiny bit slower for half the price.

The Q9550 has been moved to the E0 stepping (from C1) as of Aug 22. The new stepping will take some time to replace the older stepping in stores though. I agree with cjl, save a few hundred dollars and get something a tad slower. No need to pay for a high multi when you aren't OCing. You also haven't said what you want to do with this thing yet.

EDIT: Typo

I thought I was clear about not getting the Yorkfield unless there are noticeable performance problems. The "Yorkie" will make the system more future proof as more software gets multi-core/SSE4 support.
As for DX11 unlocking the power of multi-cores, many things are already known: HERE YOU GO!
http://www.tgdaily.com/content/view/38660/98/
http://en.wikipedia.org/wiki/DirectX#DirectX_11
http://www.gamasutra.com/view/feat [...] ucing_.php
ps (also agree with randomizer)

I still would personally if it was my cash.

Ya... money spent on a mini mac, and trying to upgrade the CPU to that quad.

I see that only 'runswindows95' that got what I saw.

Anyhoo... its your cash, do what ya want.

. o O ( )

Will it fit in a mini mac?