Quote from GTS:
Even if your app is single-threaded keep in mind there are always a host of other things going on that can be run on the other processor (OS processes) so its not like it will sit there idle.
Dual core systems also tend to feel more responsive because of this (tasks dont get cpu starved)
Go for the core 2 duo.
Edit: You may find this article useful: http://www.tomshardware.com/2007/03/26/the_gigahertz_battle/page13.html
Quote from GTS:
Even if your app is single-threaded keep in mind there are always a host of other things going on that can be run on the other processor (OS processes) so its not like it will sit there idle.
Dual core systems also tend to feel more responsive because of this (tasks dont get cpu starved)
Go for the core 2 duo.
Edit: You may find this article useful: http://www.tomshardware.com/2007/03/26/the_gigahertz_battle/page13.html

Quote from a529612:
If you want something cheaper, just buy AMD x2. I'll pick x2 over Pentium D anyday.
I didnt write the article but imo no serious trader should be using an overclocked PC so your question is moot in this context.Quote from Bernard111:
Why don't they compare a core 2 duo with a good pentium D 945 overclocked @ 4 Ghz? You will have 2 cores running at 4 Ghz and why don't use the affinity feature on Task Manager to assign specific applications to the 2 CPUs?
Quote from GTS:
I didnt write the article but imo no serious trader should be using an overclocked PC so your question is moot in this context.
PS: You can edit your post (instead of posting twice)