In talking to a developer who wished to remain anonymous, gamers will see a difference on Day One when they compare third party PS4 games to Xbox One head-to-head. The developer told me the PS4 is 40 percent more powerful than Xbox One and games like Call of Duty Ghosts will be noticeably different out of the gate.
In the past, Xbox 360 games looked better out of the gate and over time PS3 games progressively improved to the point where games like The Last of Us and Beyond: Two Souls stand out even against some next gen titles. But if this differentiator holds true, not only will Xbox One games have DRM issues and no rental options and limited used game opportunities, the games won’t look as good as PS4 titles. That sounds like a perfect storm of negativity for the hardcore gamers.
This processing power issue also could be a potential reason behind the latest controversy that has emerged for Microsoft at E3, in which photos were taken of some Xbox One games running on Windows 7 PCs with NVIDIA graphics cards. Sony PS4 developers took to Twitter saying PS4 demos were running on PS4 dev kits. I know playing PS4 games behind closed doors that the PS4 was clearly visible as I played.
Source - PS4 Sold Out At Amazon - Forbes