Sony took thermal issues very seriously with the design of the PS3 from the get go, Toshiba engineers also played a good part in this also FYI. The end result is a very good achievement I would say.
But I would imagine all games will cache to the hard drive though off of the BD in order to reduce load times. Which would of course make sense. I wonder how the HDD will be divied up in terms of dedicated storage.
There's a massive difference between using a cache and booting directly from the HDD. For example, games installed on my XBOX HDD load about 3-4x's faster than the retail disc, usually I can't even read the load screens.
