I have now a Pentium D 960 clocked at 4.16 GHz.
I'm looking for a new quad core CPU. The Q6700 or the Q6600 are interesting. But are these two CPU's better in game performance than an overclocked Pentium D 960 at 4.16 Ghz. The Q6700 runs at 2.66 Ghz and the Q6600 at 2.4 GHz. That's a big different with my D 960.

LoL are you serious? Why dont you check what your cpu scores in 3dmark06 and then check what a stock q6600 or q6700 scores. Besides your OC what you got so odds are you wont be running a quad under 3.5.

Yes. The C2 architecture is so much better than the Pentium D that there's no comparison.

Most of posters replying, however, will tell you that since most games still do not support C2Q, you will get more gaming performance out of something like an E8400 which can also reach 4 GHz. Based on some benchmarks I saw in an issue of PC Pro (British computer magazine) when the C2D's first came out, an OC'd E8400 is at least 1 1/2 to 2 times faster than a D960.

This should give you a general idea. You should be able to estimate the correct scaling of a 4.1Ghz D960.
What you didnt mention was what games are imporant to you, video card and monitor resolution you game at
For example for if you have a NV7950GT or HD2900Pro and a 20" 16x12 res monitor you most games will be GPU bound and you'll get the same performance between a stock D960, your OC'd CPU and a Q6700 (QX6700 in the chart).
On the other hand if you game @ 1280x1024 and play UT2004 that chart could be accurate

I have an Nvidia Geforce 9800 GTX and i play mostly @ 2560x1024 (2 screens) or 1280x1024 in games like Crysis, Lost Planet, ...

You're not making this easy - are you?
Harder to guess-timate how much better a stock 2.66Ghz Q6700 will be in those different conditions.
With your 15% overclock on the D960 and the Q6700's ability to take an easy 25% overclock I'd make a SWAG that the chart above would hold up in terms of % improvement (rather than FPS) for 12x10 gaming. At 25x10 you'll be GPU bound and maybe not see a major improvement.

I agree.

Generally speaking however the quad will be a fair amount faster then a Pentium D

I think an overclocked Q6700 would wax the floor with a Pentium D. The newer and more complex games would make the difference even greater. As already mentioned, an overclocked e8400 would probably make an even greater difference. It should be remembered that its not just the clock speed, but the amount of work done per clock. I personally prefer quads, as I think the coming games will take more advantage of the multiple cores than the present games do, but that's an opinion and nothing more. Of course, if a person does lots of multitasking, then a quad gives good advantage.

i don't think so guy sorry !
a simple Quad@2.6 is NOT better than a D960@3.6 in a MONOTHREAT task.

If the application/game is not build to run faster on multithreads/multicore hardware, THAN the clock speed still the main indice to compare them and not the cpu architecture.
So in MONO, D960@3.6 runs faster than Quad@2.6

BUT

in a multithread application (like cinebench) the clock speed isn't a right indice.
So MULTITHREAD, D960@3.6 IS VERY SLOWER than Quad@2.6

have a good day !

I don't agree with the above post, the Quad with the better architecture will be better than the Pentium D as well as the amount of L2 cache that's in the quad, that most games use. As we remember clockspeed doesn't mean everything, its how fast they operate at their clockspeed.

Lol, yeah. Newer quads can literally execute 4 times the instructions per cycle per core compared to Pentium D. 1ghz = 4ghz. Unless the Pentium D gets chocked on low cache, in which case the difference will be even bigger.

Not sure if anyone remembers the legendary single core old type celerons that goes to 5ghz on air. Ghz is everything!

Fixed.

Meh, it's not funny anymore.

I didn't intend it to be funny...

It's the truth.