Odd E8400 behavior

Well, I had to replace a dying MSI P965 Platinum with a P35 Neo2, so I figured what the heck and got a shiny new E8400 to go with it. Just arrived yesterday and has been running very smooth.

However, when I run speedfan (running VistaX64 so no luck with Coretemp or TAT) it registers core 1 & 2 temps as about 37/31, which seems oddly divergant. If I start stressing it with orthos core 1 jumps to 52, and core 2 doesn't move much, if at all.

My guess is that temp sensors for the E8400 simply aren't accurate yet. Should I be worried that one core isn't touching the heat shield properly? I've never seen temps so divergent. My E6400 was rarely more than 2C off between core 1 & 2.

I'm using a Zalman 9500 which I love, and had great luck with for my E6400.

Any thoughts?

Yeah I'm not worried about 53C per se, but that doesn't leave me much room to overclock. One would expect a move to 45nm parts to allow some pretty good leeway.

Given a 20C difference on the Cores at load, and the 2nd core not even budging, I'm going to assume that Speedfan is just flat wrong.

Hope they come out with a new version of Coretemp or TAT. I prefer knowing my temps before tickling the FSB and Vcore.

Possible reasons as to why one core got hot and not the other is if the stress tester only loaded one core. Check that out to be sure its loading both cores by using task manager.

Actually even with a higher temp the new 45nm parts will leave you some leaway as they will be able to OC higher using lower voltages thus giving you cooler temps at the same speed as the old 65nm parts.

I really want a noce Q9450 but am tempted to just wait until Nehalem comes out at 32nm instead to see the potential of those babys.

¿Have you checked the processor temperature in the BIOS?

I use HWMonitor available from CPUID.
http://www.cpuid.com/hwmonitor.php
I don't know if the program works on Vista 64. I have not used it on a 64bit OS.

I agree that there may be something wrong with the readings from the 8400's. I have seen many people complain about drastically different readings from each core. On mine they are withing 2~3 degrees at load but always read 42 for both at idle, never been 41 or 43 but always 42 (these readings are from coretemp and hwmonitor). Not the same thing you are seeing but strange also.

Also there is a big difference from what the motherboard reads (smart guardian) and coretemp.

There's been a ton of reports of people getting weird temperature readings with the new E8x00 chips. Some people are reporting that their temps on both cores stay fixed at certain values, and only change once the actual chip temps go above those fixed values. In other words, if the core temps are below those values, they aren't being reported accurately.

Speculation is all over the place regarding the cause. Some people say it's probably a Bios issue. Some say it's an issue with the monitoring programs like Coretemp (although the author of the software says it's working correctly), and other people are saying it's an issue with the chips.

From what I've read, it's looking more and more like it's an issue with the temperature sensors in these new chips.