I-Baton

Anybody have opinions of external optical drives? That would sort out a lot of difficulties I'm having finding Laptops that meet my needs. Do their speeds suffer compared to an inbuilt optical drives, if so, then how much?

I currently have a reasonably heavy HP Pavilion as my daily driver that's 6lb's (Although I live in Australia, so I had to google what on earth 6lb's is) So that's no problem. I love the larger screen, although the battery life isn't fantastic I use it for media consumption, and anything smaller would suck.

I want the dedicated graphics because I'm doing Engineering and will be running some CAD programmes on it. (forgot to mention that in the question) How would a Duel Core with 4 logical cores compare to a Physical Quad Core processor? I.e, The i5 7200U vs i5-6300HQ

I'm looking for a Quad-core (i5 or i7) laptop for around $1000 USD, it must have an optical drive (that can read blue ray, DVD's and CD's), have a greater than 16" Full HD screen with dedicated graphics and a 1TB HDD and 8GB-16GB or RAM. This is for a multipurpose Machine including audio production, minimal gaming (Not running crisis or anything, just things like KSP, CIV5 etc.) and I'm also doing Engineering So I'll be running CAD programmes on it. I realise a desktop would be better with a daily driver laptop, but it is a lot less convenient and I wouldn't get the use out of a desktop. Any suggestions would be lovely.