Upgrade options are close to none in the laptop departments you’ve mentioned, at least here in India. There are some options abroad but those are limited to a few countries and laptop models. Please keep these in mind before you choose.
The graphics solution in DV6 is better. However, you get Full HD in CB45 (for PS and HD movies).
Also, the amount of memory in the dGPU seldom matters. It’s the capability to use that memory you need to be concerned about (no. of shaders, core clock speed, architecture and features). The GT630M in the HP will give you 10-15% increase in graphics capability over the HD6630M in the Sony. However, in the Sony, it always has to handle 1080p.