the fact that you dont game makes me lean towards recommending the i7 -- more cores = better for multitask
it is 300 more tho, thats alot....i hear i7s desktops can get hot, but only due to oc.
i have an i5 750 desktop and i love it, not that there is alot of overlap between desktop and notebook preformance
i had a dell xps 15 incher a while ago (ending up breaking down just after the warrenty was up, but it got pretty ******* hot, so you are right to be concerned about heat)
photoshop can eat up memory, but you have to be doing quiet a bit to fill up 4 gig, as such you probably wont go much past it even if u do. so i wud say let a page file handle the rest. i would take the difference between 4 gig and 8 gig and use it to finance the processor. or use the cash to upgrade the hd. i hear ssds are some of the best upgrades u can do for your machine, notebook or desktop, cant wait to try one out!
also be advised turbo boost disables cores...i think. it will oc 1 or 2 cores automatically to get a bit more clock speed out of the processor, but it does so by disabling the 3rd and 4th core...or something to that effect. so dont let the stats about turbo boost sway you into getting an i7.
i have to go along with old mates reply. dont read too much into the turbo boost its full of crap.
i have a 4 year old athlon 64x2 desktop, 6 gig ram, win7, 896mg gtx260 video card (obviously that card aint 4 years old)...anyway, running chief architect on both that and a brand new hp pavilion dv6 i7 q720 processor, 1 gig ati radeon video card, 8 gig ram on the motherboard. i thought it was going to be a fantastic laptop for running chief architect.
the long and short of it is this,
the 4 year old athlon absolutely runs all over the laptop...its easily twice as fast running this CAD application. after some researching today heres what i have found out...
don't buy a quad core machine unless the software you are running is totally....and i mean totally, capable of utilising all those extra cores. if the software cant accomodate a quad core machine you are blowing fumes out the tailpipe all for no extra performance....in fact, you'll actually lose performance...dramatically!
you said you were running photoshop...find out if the version of photoshop you are currently running is capable of utilising the full extent of quad core technology. if not, i would definately not go that way! you will get a dual core laptop, for almost half the price that actually runs the software much faster. i blew $1600 Australian buying this hp pavilion dv6, when i could have purchased a dual core machine under a grand that would have run my program a tjust under twice the speed. take a look at the cpu utilisation when i am getting chief to go into 3d view. its barely using 13% of the cpu resources...and its taking way way way too long to get the 3d view showing.