This isnt cache speed you are mentioning. this is cache amount, and yes it does effects.
for example you are a library subscriber, and the librarian has got a small shelf beside his table that has got hottest books, means fastest access to them, as if the librarian has to look for a book asked, he'll first look for it in that shelf (this is level 1 cache)
he has another slightly bigger shelf around its table, after looking for book, he'll go into that shelf, (consider it L2 cache), and at last, if he couldnt find books in both, he'll go into the main shelves of library, which obviously takes time as its huge.
cache works in same manner, very fist shelf is in fastest access, 2nd is after first and so on. so in processors, the CPU first looks for executable data in L1 cache, so bigger cache is, more data it can hold (and vice verca).
P-4 EE (so called Extreme Editions) have another level of cache in them, and that is L3 cache (2MB), while others (in northwood core) are having L2 = 512 (and non L3).
this EE (also termed as Prestonia) L3 extra, besides this L2 = 512K. if you see the Price tag, it wont be of that much worthful to buy (unless u have recently won a million$ lottery).
you can add more RAM, or as well, buy hard drives with 8MB cache buffers (see cache came again).
and as you mentioned Barton, think again, Bartons are with 128K (64K for instructions and 64K for data) L1, as opposed to P-4's with 12K (instructions) +8k (data)
and also, why are u comparing Bartons with P-4 EE? this Ee edition came when AMD launched their 64-Bit processor, so keeping in mind price comparison, compare EE with FX.
Intel Core2Quad 2.66Ghz 12MB L2-Cache
4096MB DDR Kingston Hyper-X
XFX 9600GT AlphaDog
Seagate 2 X 320GB SATA2
LG L246WH Flatron 24"