Wasnt GDDR5 too expensive and therefore MS went with 8GB DDR3 and then were suprised by Sony that they used 8GB GDDR5, because all rumours hinted at that Sony is going to use only 4GB GDDR5?
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Beiing PS4 100€/$ more cheaper and faster didnt help MS, too...
Was indeed, but Sony get to the point very quick.
What point? Well, about the time companies take to make profit selling hardware. Microsoft was so convinced about the sucess of Xbox 360 that totally forgot about that.
Sony lost money selling PS4 from around one year because of the production cost, but they know AMD chipset would eventually reduce the price over time and that software make more money than hardware, assuming you have a decent install base.
Another point in question, if you saw the video I posted, both John and Rich from Digital Foundry already knew about the Playstation 4 specs, so even them got shocked from PS4 reveal conference about Sony double the memory configuration. The PS4 prototype came with 4 GDDR5 and devs complain about the low memory size, so they ditch the ideia of selling a PS4 with the camera. So, PS4 with 2x 4 GDDR5 and removed camera sense for reduce the launch price.
Not only the DDR3 was a bad ideia, but rely in the SRAM was also a bad move. All the pieces together, the cost, the specs, the forced kinect and the DRM.
Microsoft even OC some of the original Xbox One configuration.
edit: BTW, the rumors are true. Microsoft source got right. PS4 prototype came with 4 GBDDR5, but even with less memory I got shocked they knew it Sony would use GDDR5 and still opt for DDR3. GDDR5 are superior over DDR3 in gaming. Microsoft move (or lack of move) don't make any sense.