Given the already high production prices for the PlayStation 4, and similarly for the Xbox 720, i seriously doubt at this point in time Microsoft would increase the memory or switch any components from the existing design 'to compete', when the overall amount of memory is the same, they will already be in contracts with the CPU/GPU manufacturer, AMD with the custom design finalized and ready for mass production, to be ready for the initial batch of consoles, this leaves Microsoft with two choices - Continue with existing spec and attempt to undercut sony on pricing to drive the sales (genuinely, i believe fully that launch prices will be very similar or the xbox 720 20-70usd less), or, they go back to the drawing board, redesign the CPU (sorry but you can't just switch from DDR3 to GDDR5 without redesigning the memory controller and all the supporting hardware), motherboard and cooling solution, possibly causing the release of the console to slip.
Look at it from microsofts perspective:
Release as-is and undercut sony on price, or
spend millions redesigning, piss off AMD for changing the finalized cpu/gpu design, increase the hardware costs and as a result, end up coming to the market late, behind Sony, with very similar or identical spec, either making less per console sold or losing more per console sold due to hardware update, and for what?.
Logic alone suggests that they'll just release as is, because the consequences of changing things now are not beneficial in any way, to Microsoft.







