Questions about Vaio Y Series

Hi all,

I'm looking for a ultra-thin-and-light laptop to replace my current ThinkPad because I will be commuting on foot for a long distance with my new job. I am seriously considering Vaio Y series as my next laptop but I haven't found any reviews as detailed as you may find on NBR, leaving some questions unanswered.

The product page specifies that it has a magnesium casing for better rigidity. Is the magnesium material only on the exterior, or is the entire frame made of magnesium?

The product can be customized with ATI Radeon 4550HD. Since I will be using research applications with some moderate to heavy graphics (3D biochemical modelings, etc.), this is essential. Is the graphics card switchable if configured with ATI?

Vaio Y series comes with either Core i3-330UM or i5-430UM. I understand that the Core i5 version offers TurboBoost, but is it really worth the $100 upgrade? How is the Core i3 in terms of performance if coupled with ATI graphics card?

Lastly, how long has it been since Y-series was first released by Sony?

Thank you all in advance.

 

ATI does not do switchable graphics and I think the Y series was realeased earlier in the year and the i5 is from a quite recent refresh.