Does this seriously affect performance that much, or is it not noticeable?
Yes, it definatly effects performance.
I'm running an AMD Athlon 64 X2 Dual Core 3800+ which has a clock speed of 2 GHz (not as fast as many processors out there) and I have noted a big difference in performance, particularly with multitasking. I am able to perform heavy load operations (ie resizing 100's of pics or video encoding) and the overall performance of the machine is effected very little.
So, if you use heavy applications or many applications at once, dual core is definatly a big help.

And price aside, which is "better" (irrelevant to company preference )?
Like others have said, it mainly depends on your requirements - it seems that Intel are better for laptops and AMD are better for desktops. I have something to add to this however - it is not just a choice of "do I want a laptop or a desktop", it also depends on what applications you will mainly be using. I believe in some cases for pure video encoding Intel tend to come out slightly ahead?

On an additional note - I have noticed that some software (usualy games) do not like using 2 cores AT ALL and simply freezes at some point. With these I have found that just limiting the program to a single core tends to sort things out.

In any case - judging by the majority of literature I have read that the AMD CPUs are the better choice for desktops, particularly when price IS taken into consideration (and I expect that there are very few people who can choose to ignore price).


omin