Confused with CPU naming - which is quicker?

[TheBigCheese]

Hi guys

I'm considering having a custom built laptop and there are several processor options but I'm a bit stumped which to pick.

I am looking for raw processing power as the machine will be more of a number cruncher (Photoshop and video encoding) rather than a games machine.

The options are:
P8800 - 2.6GHz 3MB cache - dual core
T9600 - 2.8GHz 6MB cache - dual core
T9700 - 2.6GHz 6MB cache - dual core
T9900 - 3.06GHz 6MB cache - dual core

The quad core versions are too expensive to consider.

However...tonight I've found that I can get a proper i7 which I had no idea you could get in a laptop...that's upset things a bit!

i7 920 D0 2.66GHz- quad core
i7 950 D0 3.06GHz - quad core

Now I'm assuming that an i7 920 will be significantly faster than a P8800, and an i7 950 will be significantly faster than a T9900...but are they fast enough to warrant the extra expense?

My Google skills seem to be failing me tonight and I can't find any comparison charts that show all the processors under the same tests.

I am completely out of touch with what i7 is capable of (though I know it's great for overclocking...but not in a laptop I presume), but notebook processors are a mystery to me...the last laptop I got was over 4 years ago...netbooks are probably more powerful than that now!

Any thoughts or guidance would be most appreciated!

Many thanks

 

[TheBigCheese]

Thanks for the posts guys though I think some of you may not have read my post closely...it will be going into a laptop so no way can I overclock it...not without melting something that's probably important!

I like the idea of the 18.4" screen with the macro keys at the side but they only come with the T series of mobile processor...will there be much difference in capabilities between those and the i7 920/950?