Passive Cooling for CPU's

I'm in the proces of planning / building an HTPC around a silverstone LC16M case. Does anyone have experience of passively cooling modern CPU's?
I was looking at the AMD 'EE' series and wondering if this is possible with a big heatsink / casefans only.
Any thoughts?

Yes, you can passively the AMD EE CPUs. People have been passively cooling the Athlon 64 X2 3800+ thru 4600+ for a few years now. You can find this info in the www.SilentPCReview.com forums. I've even seen some posts about a few brave souls who were passively cooling the X2 4800+; it's pretty rare though. Those people use massive heatsinks and the case must have good airflow.

The Silverstone LC16M seems to have fairly decent ventilation, but it is only about 6.7 inches tall or about 170mm. That's relatively short for a large heatsink. I use a Scythe Ninja to cool my E6600 and before socket AM2 hit the market, it was one of the most widely used heatsink to passively cool CPUs. Scythe Ninja (rev. B) is compatible with socket AM2 now, but it will be too big for your case. It measures about 150mm tall or about 5.9 inches. But it needs to sit on top of the CPU so the approximately 20mm clearance is definitely not enough.

The limited height also prevents you from using the Tuniq Tower which is also a very good heatsink to passively cool your CPU. It is slightly bigger than the Scythe Ninja.

A quick recommendation would probably be the ZEROtherm BTF95 CPU Cooler. I have not done any research on this product. However, this heatsink is quoted at 128mm or slightly taller than 5 inches. It is almost entirely made of copper and is a better heat conductor than aluminum. In my opinion this is probably your best bet, unless you do your own research.

ZEROtherm BTF95 CPU Cooler:
http://www.newegg.com/Product/Prod [...] 6835887001

Its an energy efficient one. they have a tpd of 65watts and ran up to X2 4600+ i think. The Brisbane ones are based on .65nm now so the EE's do not have the advantage anymore as far as i know.

sorry i do not know of any passive coolers that fit well in that low of a case.

Zalman's 7000 and 7700 would work, but are not fanless. SilverStone also has there own NT01 cooler that may fit and if its close to the rear fans may do the trick.

A good low speed fan cooler may be best.

EDIT
jaguarskx beat me to it. i think it was the EE SF ones that are 35 tho?

EE = Energy Efficient series. Rated at 35W TDP and limited up to X2 3600+ or X2 3800+ (to the best of my knowledge).

They are kinda hard to find, then again I haven't looked. The 65W and 89W TDP versions can be found everywhere.

3600 is easy to find now.

With the big heatsinks, passive cooling is possible even with highend processors. For example I can run a E6600 at 3GHz/stock voltage with a fanless Ninja and a single 900rpm 120mm case fan and still have about 15C of headroom left before throttling while running dual Prime95. Or I can run the E6600 at stock speeds but undervolt it to 1.1V and have around 30C of thermal headroom.

there are lots of 65 tdp 90nm a64's they where hand picked cpus that would run @ stock speed with less voltage

that what the EE's are

A64 x2 4600+ EE 90mn 65 tdp

the EESFF's(though it was EE SF....but its not) where supposed to run cooler(i think thats where the 35watt 3800 came from). but to be honest a stock e4300 runs as cool.

my vote goes for a Brisbane CPU. with the cooler recommended above(the butterfly thing) if it fits.

not on that site.

i have not seen one of those in a while. i think dell took em all

just search for a x2 3800+ EE

Specs
look at the voltage

this is the non sff one

Toms Hardware did a article on this Page 2 shows the EE SFF ones specs. toms shows good power on EE's and EE SFF. yet other sites show e4300 as the same....hmmm i will trust toms

http://www.newegg.com/Product/Prod [...] pr1c3watch

The one issue that I see with Passive cooling is that it gets very very VERY hot. Just look at the XFX Fanless 7950GT series, they have been reported to go up to 115C! Thats hot enough to kill a moose at 400yards!

I just finished watching some videos online on my dads Inspiron 8600. I kept the laptop elevated the whole time, yet around half of the bottom surface of the laptop got INCREDIBLY hot. I dont mean hot as in "ow thats hot", I mean hot like the surface of the sun! And that PC is running a centrino Banias 725!

I have to get my dad a laptop cooling pad.... any good budget ideas? It would be fun to make one, throwing like 8 120mm fans into a bracket and powering it thru an AC adapter... but thats too smart for me. Im just looking for a way to stop getting burnt... for cheap

how sweet would that be?

@ all - last cpus I passive cooled where celerons 466 and 800. The 466 was with a P133 passive heatsink and the 800 was with a Athlon XP 1800 stock heatsink with the fan off

But for a test i did run my current system with the fan off folding @ home. Did not get past 60(thank you 900, it went to 70 in my Sonata II)

although a core 2 would be better, esp if you going to advance to HD in years to come, there are Passive cooler out there such as Coolermaster GeminII