[G4] Liquid Cooled new g5 2.5 ghz

[Joseph B. Gurman]

     Steven wrote:

>It seems to me that if I read the diagram correctly one of the
>processors will be much hotter than the other...

     The diagram is a little misleading, as it shows only one fan and 
only one liquid-coolant radiator. If the pictures of the G5 innards 
are still correct (and have not been changed to those shown on the 
AppleInsider Website last week), then the 2 x 2.5 will still have 
upper and lower fans corresponding to upper and lower CPU's, and the 
marginal difference in temperature caused by convection of heat from 
the lower processor should be handleable by the upper 
fan-plus-radiator combo.

     Of course, this isn't quite like a car or (even more so) a 
motorcycle, which can use the speed of the radiator through the air 
to carry heat away a lot faster than the fans can.... unless you plan 
to strap your G5 to the hood of your 'Vette.

     Seriously, this design, cool (no pun intended) as it is, 
represents a setback: it means IBM isn't producing enough 970FX 
chips, which produce much less heat than the 970's thanks to smaller 
die size, to roll them out in desktop machines. To deal with the > 
50% additional thermal output of a 2.5 GHz processor relative to a 
2.0 GHz one's, Apple's had to add liquid cooling. For that matter, 
has anyone heard of anybody who's received a dual G5 Xserve 
(970FX-powered) yet? We're still waiting for ours....

						Joe Gurman
-- 
"I love deadlines. I like the whooshing sound they make as they go by."
                                                          - Douglas 
Adams, 1952 - 2001

Joseph B. Gurman, NASA Goddard Space Flight Center, Solar Physics
Branch, Greenbelt MD 20771 USA