Question about temperature scale from the Core 2 Temp Guide

[mrknowitall]

I am a bit confused here, Compu. You list the following temperature scale in the Core 2 Duo Tmperature Guide

Tcase/Tjunction

--70--/--85--85-- Shutdown
--65--/--80--80-- Throttle
--60--/--75--75-- Hot
--55--/--70--70-- Warm
--50--/--65--65-- N
--45--/--60--60-- O
--40--/--55--55-- R
--35--/--50--50-- M
--30--/--45--45-- A
--25--/--40--40-- L
--20--/--35--35-- Cold

So 50-deg Tcase is the highest normal temp. It also states that the idle to load delta is ~25. This means that Tcase at idle is 25-deg. That's not even warm...if my wife were in charge of the thermostat it would always be that warm in our apartment.

In fact, lets say it's summertime. We have no airconditioning, but it doesn't get too hot because we live right by the water. So let's say ambiant is 28-deg. Now assume Tcase is at least 2-deg warmer than ambiant, add another 25 degrees at load, and Tcase is at 55-deg...WARM. If were 32-deg ambiant , the processor would be HOT.

I'm guessing maybe the idle to load delta changes with the cpu frequency? I guess this is something I should have noticed or looked into already. 25-deg is max delta with a hefty overclock. And idle to load delta is significantly less at stock speeds?

 

[wchp]

Unless you consider that a E4300 (for example) with the Stock HSF at 22C ambient runs about 40C/55C at stock speeds at 100% load. This gives you about 15C headroom for OCing.
You would still need to factor in your geographic environmentals (or the spouse factor) and adjust your OCing targets accordingly.

So figure with stock clocking and stock HSF at 100% load you would still be within acceptable range with your ambient temp @ 37C (98.6F)
Also consider that you will rarely ever get both cores to 100% for extended periods with real world utilization. TAT is being used for stability testing.

So if you pick up a E4300 or E6300 and get into the 2.8 to 3.0 range with 5-7C of headroom left by simply adding a $30-$60 HSF your still way ahead of a $800 + CPU for most real world applications. Anything beyond that is just icing on the cake for those that got lucky with their CPU or are throwing some more money at cooling (just ask the waterblock folks - there is another post in the forums where they are running a E4300 @ 3.2 @ 1.485v 8O and getting 70C)
If we use the guide we are also presuming a Tjunction of 85C which is a close approximation based on other information, but as close as we are going to get with the tools we have. So pick your target on how close to the edge you want to get, that lets you sleep and not worry about the chip turning to toast. I run my E4300 at 3.0, my A3 2.0t chipped to 265bhp and sail with my spinnaker up in 20knots with sea anchors out... it just depends on what you are comfortable with.

 

[CompuTronix]

mrknowitall and wchp, systems which have a low Heat Score will run less Delta and lower Idle and Load temps on the scale than those with a high Heat Score. In high Ambient conditions, OC and Vcore may need to be reduced. The most predominant single factor relative to heat is Vcore. Your best OC is TAT at 55 Tcase / 70 Tjunction, and Orthos at 50 Tcase / 65 Tjunction. Also, TAT is designed for short duration Thermal Analysis, and not for stability testing.

Hope this helps,

Comp 8)