Nvidia GeForce GT 740m (64bit) vs Nvidia 640M(128bit)

Hi guys.
I've been searching a lot for my next laptop and I arrived on to two laptops which are quite similar in performance, I think. Here are the specifications of each of them:

Lenovo Ideapad Z500 (59-380480) Laptop:[/.]


Processor: Core i5 (3rd Generation) 3230M
System Memory: 4 GB DDR3 1600MHz
HDD Capacity: 1 TB
Operating System: Windows 8
Screen Size: 15.6 inch (1366x768 pixels)
Graphic Processor: NVIDIA GeForce GT 740M 1 GB [DDR3 version with 64 bit bandwidth]
Here is the screenshot for the card in the laptop:

Image http/img2.uploadhouse.com/fileuploads/18237/18237391bc2cd03c6875fdeaf93ca8e5eb31cd99.gif


Next laptop I'm looking at his : Dell Inspiron 14R SE Laptop

Processor: Core i5 (3rd Generation) 3210M
System Memory: 4 GB DDR3
HDD Capacity: 500 GB
Operating System: Windows 8
Screen Size: 14 inch (1366x768 pixles)
Graphic Processor: NVIDIA GeForce GT 640M 2GB (standard version, no changes)

I don't think I need to provide a GPU-Z screenshot for the 640M as there is no change in the card

I'm knowing that the 740m is better but as it is having a 64 bit bandwidth, I'm a bit hesitant to buy it. The 640m looks promising but yet it is not better than the 740m standard version or perhaps this version too. The model with 640m also has slightly weaker CPU, and less harddisk.

So, please guide me which one should I get? My need is that I have to use the laptop for programming, Game developing and of course gaming, If you can get a better model in the same price range suggest me that too. Your help will be very precious and valuable to me. Thanks