Heatsink vs Temperature diode difference Mac Pro (mid) 2012 12core 5680 3.33 Ghz CPU's

UPDATE:

I replaced the thermal past on both the CPU's and the Northbridge chip. Here are the results, and they are impressive!

These temperatures are running at full load on CPU A, and 40% load on CPU B, using Handbrake, encoding an 1080p program.

Thermal Paste used: Arctic MX-4

CPU A shows the following:

Heatsink - 130F/55C

Diode - 157F/67C

27F/12C degree difference, (53% reduction in temperature difference between the heatsink and diode, from prior readings.)

[thermal past was dry when opened for replacement.]

CPU B shows the following:

Heatsink - 122F/50C

Diode - 147F/64C

About a 25F/14C degree difference, (12% reduction in temperature difference between the heatsink and diode, from prior readings.)

[thermal past was still wet when opened for replacement.]

Processor cage & heatsink fan speeds changes:

Before thermal paste replacement:

CPU A&B boost fans, (3200 rpm)

Intake/Exhaust fans, (2000 rpm)

After thermal past replacement:

CPU A&B boost fans, (2496 rpm)

Intake/Exhaust fans, (1279 rpm)

Thanks danallenhouston

It looks like your test, if I'm reading it right, shows a 14C difference at full load between the heatsink & CPU "A".

That is way different than mine and worries me.

I'm using handbrake to encode 1080p video, which is what is putting the heavy load on my CPU "A", I'm seeing a 33C difference between heatsink & Diode on CPU "A"

So the question about replacing the thermal paste seems to be yes.

Anyone else out there concur?

Thanks again danallenhouston.

PS: Grant, yes you are correct, we are talking about the same part.

Another Update

After running the processors for 10 days, (at full load, described in above post) things have improved even more.

[FYI: running fans with TG Pro set at above 145° / CPU A / 33% fan speed. There are more settings, higher and lower, but this is the one that the Mac settles at.]

Here's the temperature/fan speed stats:

Logic Board Ambient: 85° F / 29° C

CPU A Diode: 143° F / 68° C

CPU A Heatsink: 126° F/ 52° C

CPU B Diode: 136° F / 58° C

CPU B Heatsink: 117° F / 47° C

North Bridge Diode:149° F / 65° C

North Bridge Heatsink: 120° F / 49° C

CPU A&B boost fans, (2137 rpm)

Intake/Exhaust fans, (1152 rpm)

I should have also posted the ambient Logic Board Temperature 86F/30C for the above post.