Cheap PCs from Wal-Mart - heat

Alvin Oga alvin at
Mon Jun 2 03:32:59 EDT 2003

hi ya mark

On Sun, 1 Jun 2003, Mark Hahn wrote:

> for instance, compare:
> 	"light": 1U via/PIII-class server, $170 1U chassis
> 	- probably cheaper per unit.
> 	- probably cooler per unit.
> 	"heavy": 1U dual Xeon/Opteron server, $350 1U chassis
> 	- definitely faster (CPU, cache, dram, network).
> 	- definitely more reliable.
> 	- probably denser.
> 	- definitely hotter per unit.
> 	- definitely more expensive per unit.

actually, both cases can be identical ...
only major differences can be types of fans for airflow
and wattage of the power supply

thickness of the steel also makes a big difference to reliability
of the 1U server

> I consider heat the only serious issue with the 'heavy' approach, and there's 
> just not much we can do about that except hold our breath for .09 ;)
> like heat, reliability is a huge concern mainly for large clusters - you 
> definitely don't want 512 noname powersupplies, or the kind of chassis 
> where the vendor doesn't realize that extra fans are a liability.

fans vs cpu temp  vs cooling mechanism implies a specific cooling
mechanism instead of generic solutions with lots of "useless" fans??
	- if you look at the airflow, most of the fans don't do anything
since 8 good 40x40x20 fans is about $100 retail... it'd make sense to use
some other more cost-effective cooling of the cpu heatsink
	- yes you can buy $3.oo fans... but, you get what you pay for ?

> the motherboards would still be standard/commodity/non-proprietary,
> and could even have passive CPU heatsinks, and just a minimal tray to 
> screw each MB onto.

passive heatsink w/ proper airflow works much better than those
itty-bitty fans clipped on top of the cpu heatsink
 	- fan blades needs ( say 0.5" of air ) to bite into to generate
	airflow and cooling of the cpu

	- air flow blowing down onto the cpu and bending 90degrees
	sideways is not helping the coooling air stream to cool the cpu

- we put our cpu fans on the side :-)

have fun

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