i7 720qm vs 2630qm

How much o a regular performance difference will i see. I know the clock speeds are faster but will there be perceivable performance difference. I mean in terms of boot time or multitasking performance. I will also be adding an ssd, if that matters. Shall i go with the older one or get the newer one.
In context, i am thinking of buying the Alienware m15x, or the m14x. And I am from India and the m15x is available here with gtx460m and 1080p screen, 8gb ram for the same price as the gt555m 1.5gb 900p m14x. Portability and battery life difference between them is not an issue but i believe the m15x will perform much better than the m14x. Am i right. But in terms of pure processing power(disregard the GPU) how much of a performance difference will there be between the two. Should i go with m15x even though it has older gen hardware( bluetooth 2.1 vs 3.0, no usb 3.0, only 3 usb ports vs 4 in m14x).
Also another completely different question, i thought of creating a different thread but i figure why not just squeeze it here- I have a laptop which has 2 ram slots. It came with a factory fit 4gb 1333mhz samsung ram. I am thinking of expanding the ram to 8gb and should i get 2X4gb corsair 1333mhz ram and replace existing one or get a single 4gb ram 1333mhz. Basically will running two seperate branded rams casue problems, Cause i heard both rams need to be same or i'll get BSODs.

 

it's a pretty significant difference. the sandy bridge crushes on both single core apps (games) and even more so in multicore tasks.

 

Hey there

look here.

I think i7 2630 is a better choice; cheaper and worth the money.

It's wise to have two or more rams from the same producer.

if you want to custmized your laptop, then Clevo is good brand.

Regards,
Valentin N