ok a few questions before you guys further discuss this.
1) will you be keeping the laptop for a few years?
2) how often will you be carrying it without docking?
3) how serious are you about your work?
now, if you're keeping the laptop for years then going all in would save you frustrations, like pushing the processor you can buy to the furthest, including a GPU or not, including an SSD(its a must in CAD imho), and so on.
if you won't be keeping it for more than lets say two years then go get something "just right" and just purchase a better one later on.
example: (span of 4years)
just right laptop 800$ - 2years = 800$x2 @ 4years.
maxed laptop 1400$ - 4years = 1400$ @ 4years.
note: you save 200$ in the long run.
if you'll be carrying it plenty and on long durations without docking then a quad would drain your battery too fast, you may be able to use CAD for two to three hours before your laptop hybernates.
if you're really serious about your work then building a workstation with a tesla will save you more worth than going with a power laptop, you could pilot your workstation with a good enough laptop remotely and make the workstation render the works for you.
if you aren't that serious then... pft i've seen people use their atom notebooks for CADs in collage, tho its slow but its usable.
I'll be keeping this laptop for at least 5 years. I will be carrying it around everywhere I go for about 6 hours a day.
However I will charge it here and there.
I'm serious about my work, but my laptop is not totally necessary. It will be used mainly to take notes, make graphs, and do some CAD on it. On the side I would like to do some After Effects on it, but it's not like I'm a Hollywood producer or anything, but just a note, I do have the skill to be one, on par with the special effects artist of transformers, but no where near his patience. I usually rush everything

, well I mean I'm not getting paid.
And I most definitely will not need a remote work station, ever. Also one thing I forgot to point out. Notice most laptops I choose are over 900$. Well HP lets you go without payments or interest for 12 months. So that means I have a whole year to pay it off, and I do not get charged interest. If it were any lower, I would only get 6 months to pay it off.