CPU Heat Comparison: How Hot is Prescott?
by Derek Wilson on April 16, 2004 4:32 AM EST- Posted in
- CPUs
Introduction
There are plenty of issues with current methods of comparing temperature data between processors, and we have been hard at work trying to come up with something that gives us better and more comparable results than the temperature data reported by different processors' thermal diodes. In considering different approaches, we have run into the same problem over and over: how do we measure the total heat output of the processor in any nearly accurate way.The problem with thermal diodes is that between different architectures, there isn't really a way to compare what is being reported. The diodes only measure the temperature at a specific location, and the number we can pull out of a processor isn't necessarily representative of the average temperature of its surface.
Measuring the temperature increase of the system itself has issues as well. Different components in a computer heat up as well, and there's no way to really isolate the contribution of the processor itself to this process. The only number that can truly be compared between processors is the total energy output by the surface of the chip (or heat spreader).
The heat transfer from the CPU to the outside world would be a wonderful number to have, but there is the unfortunate necessity of a heatsink and fan for modern processors to run without cooking themselves. There isn't really a way for us to get to the surface of a chip in order to measure anything. So how are we supposed to measure how hot something is getting when we are required to be cooling it at the same time?
Well, there isn't any easy way we can think of, but just because something is impossible doesn't mean the AnandTech staff can't get it done.
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Xentropy - Monday, April 19, 2004 - link
"Most of us here are not mindless zealots who believe everything we read."Unless it's anti-Intel propaganda.
"but i have seen a prescot melt motherboards"
Have you? How many motherboards? Online in some forum or on HardOCP or whatever doesn't count. Personally seen, in person, how many?
Pumpkinierre - Sunday, April 18, 2004 - link
#46 I thought that was standard with Win XP. When I looked at the idle temps., I thought that might be the problem. On my K6-3/Win98, I run Rain which does the same thing. Good Post!lesovers - Sunday, April 18, 2004 - link
The main reason the AMD XP chips are so much hotter at ilde is they do not normally implement the HALT command like the P4s. The VIA KT chipsets (266, 333 and 400) have registers that can enable the CPU to HALT. Link for this is:http://www.ocmodshop.com/default.aspx?a=125%20
My XP2000 cool down be by about 20C at idle with the chipset registers changed !!!!!!
boardsportsrule - Saturday, April 17, 2004 - link
ok wow, how can you have a 3.2 prescot be at 34C with a medeocer heatsink, when i see people complain about high temps with their 2.8 prescott using a sp-94...then onto how could a 2600+ be hotter then a 3.2 prescott...i havent seen a 2600+ melt a motherboard, but i have seen a prescot melt motherboards... this stinks of intel...wounder howmuch they are paying him?ZobarStyl - Saturday, April 17, 2004 - link
This processor is supposed to carry Intel through something like 4.0+ GHz when Tejas gets here; if it's this hot against a Northwood, how do they expect to hit past 3.8 or so without watercooling or Prometia's built into standard desktops. The question isn't whether or not Prescott is a bad processor (it's not a disaster of Williamette proportions) but whether or not it can carry the weight Intel is slated to heft onto it's back for the next cycle.mindless1 - Saturday, April 17, 2004 - link
Margalus, get a grip!Even INTEL specs it to run that much hotter. Will you not even believe Intel?
mechBgon - Saturday, April 17, 2004 - link
Margalus, I've seen several Forum members try the Prescott and go back to their Northwoods because the Prescott was running very, very hot and/or doing scary stuff to their motherboards. And these are neither AMD zealots nor newbies. IIRC one of them is running a Prometia phase-change cooling system and another is running watercooling.Margalus - Saturday, April 17, 2004 - link
I can't believe the number of amd fanatics that just can't accept reality. the prescott is not as hot as the anti intel fanatics are saying. This article was pretty well done for the comparisons they did. All of you saying how it is bs have never even used a prescott, you just listen to clueless people like cramitpal who haven't even passed 3rd grade yetAIWGuru - Saturday, April 17, 2004 - link
"Of course, we'll be there to test it out as soon as we can get ahold of a 64bit enabled chip."Why are you waiting for a 64 bit prescott? Why not use the A64 you already have?
AIWGuru - Saturday, April 17, 2004 - link
Coruscant, your understanding is incorrect.What you're TRYING to describe is the flow of (thermal) energy to the path with the least resistance - the movement of hot to cold.
What you forgot to take into account is that once the heatsink starts to "absorb" heat it may quickly cease to become the path of least resistance.
Regardless, this test is fundamentally USELESS as, unless the dissipation rate of the heatsink has been exceeded, any measurement will be the same.
Because heat does not build up on a linear scale, any measurement above that level will also be innacruate.
The placement of the probe is also somewhat stupid.