I see. But so far I used all the software that you mention, with the increase performance in CPU and GPU do help a lot. Especially when i compare a i5 and i7 laptop, the rendering and processing speed is differ a lot. While for the graphic card, many ppl would said that it not that important but i do see the difference when the upgrade of GPU. For instance a GT540m compare with GT650m both with same CPU and ram, the processing speed for autoCAD, revit, sketch up, photoshop, etc, the speed had increase a lot. So i think that GPU also play a very important role in this field as well other than CPU and ram. Perhaps the balance in between these would be more suitable.

Maybe instead of recommend you the model directly, I would like to recommend you with the spec

CPU- Go for i7, i5 would not that convenient when dealing with heavy file load.
Ram- At least get 8GB ram but if can up to 12GB is preferable
GPU- In the current trend, get at least performance with GT650m and above. Below this might not worth for the value and hard to fulfill your need and may cause you to change your laptop in short time frame.
HDD- You can try to upgrade to SSD. Even with all high spec CPU, GPU, ram but with a normal rpm HDD, the performance would be affect very much. If possible, look for laptop that provide 2 HDD slot. Another option is swap with your optical drive.
Screen- Look for FHD, it will maximize your window space especially many ppl like to use autocad with latest mode and not classic work space, those interface take up a lot of space. With FHD, it become neat and small so even with 15 inch, you still have a lot of work space. Or you may connect to external monitor. But for this field, at least get a laptop with 15inch and above is better

basically these are the need of spec for this field. So good luck in your hunting. Btw, you are studying or working?

I see.

Regarding on the ram yes. It can support. As 8GB is just like just enough. So why dun we provide extra yet the price for a ram of 4GB is not very high.

While for the FHD, even it will become smaller with the icon and the menu bar, but the empty space is increase so it just like the window in AutoCAD, with all the menu interface on, it take up a lot of model space. So that when you look at a plan, you need to scroll or zoom in and out a lot with a smaller resolution. All the icon and menu is big. For FHD 1920x1080, the menu icon become small so the model space for the plan  is bigger thus you no need to scroll that much and enhance the productivity. The most obvious software would be Sketch UP, you will see a lot of different in the model space when comparing in these 2 resolution. So go for FHD and you wont regret about it.

And i had send you a link on the seller so pls check your pm.

Autocad depends heavily on cpu processor speed