Get a pc bro... tat Budget cant get good laptop tat last long for ur usage...

that lappy for sure under stress a lot    you might not satisfy how its generating and response rate for 3D modelling anyway if me, i'll choose acer. that lenovo is over 2.5k because equip with i7.. 

can get Acer Aspire E5-574G-52UX 15.6" (i5-6200U, 4GB, 1TB, NV 920M, W10H)

oh, means you can stretch your budget until that. not really. acer is reliable than lenovo actually.. and acer still keep up with its reputation. as past many years, acer now not really the same with old acer. lots of changes.

how much do you think you can stretch ur budget?? how long will you gonna use the ACAD?

nakedtruth
U would like to know if AutoCAD takes advantage of multi threading, hyper threading and multiple processors.....

Some components in AutoCAD since release 14 do handle multi threading (for example, the AutoLISP interpreter is a thread). AutoCAD Release 14 itself is not a thread-safe application and not really a multi threaded application. For AutoCAD 2000 and later, releases do have some support for dual processors and hyper threading, but no more than two cores will be utilized. On dual-core processor systems, you will see significant increases in AutoCAD application performance, particularly for graphics and file I/O operations.

If u r using AutoCAD on a multi-processor system (i.e., more than two cores), umay see a slight performance improvement, but only as much as the operating system is taking advantage of the multiple processors.

An ARX application can make full use of multi threading as long as it is the only thread that communicates with AutoCAD . Again, this is because AutoCAD is not thread safe. Falling to do so will cause synchronization problems.

so, dual core still ok for AutoCAD

get the i5 and save money unless you really really need the speed

i7-5500U vs i5-6200U
http://cpuboss.com/cpus/Intel-Core-i7-5500...l-Core-i5-6200U

the i7 - U version is a joke man its the practically the same as i5, 2 Core with 4 Thread, its just marginally faster in speed, and has a label on your laptop which says i7 for siok sendiri only.

Now if it was the i7 with HQ version those are different class all together, 4 Core 8 Thread baby.
These are usually on more expensive laptops like gaming type.

Get Inspiron 7447.. second hand i7 should be around 2600

try check this

HP Pavilion 14-ab111TX  (i5-5200U, 4GB, 1TB, NV 940M, W10H)
Asus A555LF-XX135T A-Series 15.6" (i5-5200U, 4GB, 1TB, NV GT930, W10H)
Acer Aspire E5-574G-54DV 15.6" (i5-6200U, 4GB, 1TB, NV 920M, W10H)