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Old January 26th 17, 06:59 AM posted to alt.comp.hardware.pc-homebuilt,alt.comp.hardware.overclocking
Paul[_28_]
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Default Overclock 6700K Max Temps Prime95 Small FFT

B00ze wrote:
On 2017-01-25 05:15, Paul wrote:

Your curve seems to have a longer rise time than mine,
almost as if the cooler is being "overwhelmed".


It's a "bug" in SpeedFan - I tried again and this time I added the CPU
Cores to the graph: They shoot-up to 88C immediately, while the line for
"CPU" slowly slowly slowly rises.

Heatpipes have a limited thermal pumping capacity.
If you manage to keep all the working liquid in the
vapor phase (no chance to condense), then the temperature
shoots up. The heatpipe has some sort of "watt rating",
over which it's probably not going to pump heat like it should.
Each heatpipe has two drops of fluid in it - there isn't
a couple of ounces of the stuff. Heatpipes can also leak and
fail, but that hasn't been a problem for years and years.
Manufacturers have figured out how to make good heatpipes.
When heatpipes were still a novelty, at least one product
shipped with no fluid in any of its heatpipes. Making it
gutless.


They barely get hot to the touch tho, which I find strange - on my
laptop the exhaust vent becomes really hot immediately when I run
Prime95, not so on the Noctua cooler in my rig, it just becomes warm'ish
- I mean it's higher than room temp, but I can leave my hand there
forever and never feel the need to remove it because it's too hot...

You could try a more powerful fan on the cooler.


Yeah, I thought of that too - the Hyper EVO has a much faster fan, but I
don't know, Noctua fans are supposed to be good. Oh well, I guess I will
live with it. The only thing that worries me is whether I have bent the
CPU's PCB or not - if not bent then fine, it's how it is. And if I did
bend it, well I'm not buying another one, lol, so I will just accept
that it gets hot under Prime95.

The other issue with these designs, is "no cowling".
Mine doesn't have one either. A cowling on the heatsink,
would ensure that any static pressure the fan can develop,
goes through the fins.

Since I own a 37.5mm thick fan, if I had to attempt a retrofit,
I'd do a sheet metal cowling, plus fit the 37.5mm thick fan.
That's to get as much air velocity as possible through the
fins. I've only done one cowling/shroud for a CPU cooler here,
in the time I've worked on computers.

Air cooling goes asymptotic over about 800LFM (linear feet per minute).
Run of the mill electronics, might use around 200LFM. So there
is a point, where "mo fan" does "no good".


Regards,


There's probably a couple ways the pipe wouldn't get hot.
Likely leaving no choice but to take it apart and verify things.

I agree that the silicon die on your processor, is probably
pretty tiny. (All that FINFET goodness.) Which puts an extra
responsibility on the sole plate of your Noctua. If you had
one of those coolers where the bare pipes touched the processor,
then a couple of the pipes might be carrying all the heat. Yours
has a sole plate, so that gives a bit of spreading. The newer
processors have a thicker lid, which was added for spreading
angle too.

6700K - de-lid
https://hardforum.com/threads/6700k-...sults.1878870/

Technique demonstrated on a 3770K
https://forums.anandtech.com/threads...-tims.2285595/

The first one, shows the motherboard measurement tool showing
177W when a bit more than your voltage is applied.

The second article, shows just how thick the IHS is getting
on these processors. It's there to get spreading angle
and make the thermal footprint larger on the lid surface.

For best results, the heatsink should be oriented such
that it had the feet of the pipes going across the
thin dimension. If just one pipe runs along the die, that
would give poor cooler response.

In this picture, you could compare the three screws of the
normal socket mounting hardware, to the orientation of
your setup. I would guess they don't arbitrarily rotate
the die, between 3770K and 6700K :-) But who knows.

http://i272.photobucket.com/albums/j...0kinsocket.jpg

My CPU would be a bit different, as the die is square
on mine. And the lid is soldered down. I believe at the
time, that was part of my buying decision (4930K or 5930K).
Too bad I was such an idiot on motherboard selection, and
am now limited by a gutless VCore.

http://i.imgur.com/ZnOF6xh.jpg

Paul