Need help to buy a new laptop

[siddheshgr]

I have shortlisted a few

1-Dell 15R 5521
i5 3337U(1.8GHz),4GB RAM, 2GB AMD and 1TB Hard Disk

2-Lenovo Z580
i5 3210(2.6GHz),4GB RAM, 1GB NVIDIA and 1TB Hard Disk

3-Lenovo Z500
i5 3210(2.6GHz),6GB RAM, 2GB NVIDIA and 1TB Hard Disk

I am looking for an all purpose laptop . Web browsing, office apps , autocad , video viewing and moderate gaming . Personally keen on the Z500
My doubts
1- Does more clock speed on z580 and z500 (2.5GHz) as compared to dell 5521(1.8GHz) create a big difference in daily functioning ?
2- Effect of the different processors of both laptops on their battery life .

 

[g-unit1111]

Get a Y500, I just got one and it's a great laptop for the price I paid for it.

 

[siddheshgr]

Get a Y500, I just got one and it's a great laptop for the price I paid for it.

I have heard a lot about Y500 . Firstly it exceeds my budget by about Rs 20,000 and secondly i do not require a heavy gaming pc , i5 with a good storage and a gig or two of graphic ram is all i need .