ZeRaW wroteIt is a bit close.
I agree, I would put the difference on over-enthusiasm of engineers (which is a bit normal since they try to push their project through) and cost cuts required by the market. I even think they did put PS3 in clusters somewhere and made a super-computer out of them, but I forgot the details.
I am not an expert, of course, so I can't really measure the difference and know what it means, but it does not look dramatic to me, with my humble knowledge!