whats happened to Thermal Resistance - the death of "deg/watt"

Having been recently looking round for a new heatsink to replace my flower cooler during the hot wather i was shocked to discover that you cannot [anymore] quantify the preformance of ALL the CPU coolers arround.

You used to be able to look at a website, look at a cooler and there it told you the thermal resistance/efficiency.

It was very simple:

You see how much heat your CPU makes peak, eg 80w. assume amient pc temp is 25c. You want your CPU no hotter than 40c. You then know that you can have 15c temp rise from air entering heatsink to air leaving heatsink and you need to look for a heatsink that has a thermal resistance/efficiency of 0.1875 deg c/watt. You would probably look for 0.2 or something giving 16c rise or 41c at 25 ambient.

Anything more, eg. 0.3 and you have 24c rise or 49C CPU temp.

This was amazingly easy to work out now you have to use the new scientific reasoning... ill try not to baffle anybody with these highly technically charged examples:

"extreme cooling "
"ultra cooling "
"mega - ",
"awesom - "
"fab - "
"brill - "
"ice - "

and the list goes on.

I think that because its hard to sell your cooler against a competators when theres has 0.2 and yours has 0.201 deg c/watt capacity. It doesnt market well.

Instead 0.2deg c/w becomes "fab cooling" and
your new 0.201 deg c/w becomes "extreme cooling "

Im going to do a little experiment - get the bench suppply and a power resisitr out and test some of the heatsinks i have lying around to see how much they actually cool.

I would be interested to see if anybody does know a website where people convert "mega ", etc in to deg c/w.

If all else failes lets shed a tear and say a prayer for the decesed (apart from in catalogues such as RS who sell heatsinks for use in amps and PSU's etc.)

deg c rise/watt - may your "Delta T" last in memory.

 

I still see thermal efficiency ratings in heatsink reviews and even compared when the review compares various heatsinks. I always knew that higher(?) was better but it was just one of many factors that determined the buying decision. Some of the most important factors include cost, noise, and size (will it even fit on my mainboard?). Word of mouth and the actual review marks went alot toward it too.

You do have to admit that deg/watt just isn't very sexy. I've been trying various Socket A cpu heatsinks over the years and feel I've found one that's excellent in terms of noise, cooling, and cost. It's a Thermaltake SI-97 heatpipe with a 120mm variable speed fan hovering above it via a Zalman support arm.

It does an awesome job at cooling my heavily overclocked Athlon XP2600+ Mobile chip. But maybe the kicker was the absolutely groovy-baby look of the heatsink. It's been described as looking like the original Enterprise on Star Trek! It was a deal-closer.

Gary