your thoughts on "water cooling thoughts"

[BillA]

Originally Posted by Cathar

. . . . Thin BP blocks don't offer much in the way of thermal buffering, however, they still offer plenty of time (many minutes) for any thermal protection circuitry to kick in.
. . . . .

well, yes but not quite
the newer Intel thermal design guides discuss CPU heat sensor controlled fans (they are coming);
and make the point clearly that NO fan implementation can respond appropriately to thermal spikes as they occur too quickly

the thermal protection (by Intel) cuts in within cycles, literally faster than the temp response of the bp

what is not so clear to me is if the OCing measurement is also being diddled by the cut clock cycles
-> I suspect that Prime (for example) will run w/o errors while being 'temp protected' by cutting clock cycles;
so if clock cycles are being cut, is the indicated operating freq being reduced correspondingly ?
(a rather lot about this that I do NOT know, eh)

anyone messed with this ?
pHaestus - did we not discuss something about this some months ago ?

[pHaestus]

pHaestus - did we not discuss something about this some months ago ?

We mostly return to the same topics ad nauseum with no resolution (x equations, x-1 knowns will lead to this).

I'm not TOO familiar with Intel chips and AMD has no throttling. AFAIK there is no program that both maximizes heat generation and checks for errors. Intel used to have a good heat generating app but I suspect they are a bit gunshy w/ current state of Prescott. The discussion related to pelt cooling a P4 to a range of temps and benchmarking right? Would be even more interesting with current infernos...

[AngryAlpaca]

There are also fuel pumps. There was a little review on overclockers.com quite some time back, but the thing was noisy and not very effective (I think it wasn't effective... There was some other problem other than noise)

[Cathar]

Originally Posted by unregistered

the thermal protection (by Intel) cuts in within cycles, literally faster than the temp response of the bp

I was of the understanding that the cycle-reduction style of thermal-throttling offered by Intel CPU's could be disabled within the BIOS for many of the modern overclocking focussed boards. My Socket 478 P4 board is a little older and doesn't have that BIOS option, but I've been assured by many of the 3DMark overclocking fiends that they have the option in the BIOS and turn it off regularly as a matter of ensuring that they get the highest possible benchmark scores.

I was, however, more referring to critical thermal shutdown, as in 135C internal die temperatures for P4's, in that a CPU still does have sufficient time to react to critical shutdown temperatures.

For AMD, the Abit NF7-S board does offer voluntary thermal throttling of AMD CPU's through monitoring of the CPU internal diode, but it does not allow you to read what that diode is reporting. See section 4-4 of the NF7-S manual.

By far the majority of my testing is done with non-thermal-throttling AMD CPU's.

[Cathar]

Found it. Read section 3-6 of the Abit IC7-Max3 mobo manual which may be downloaded here.

Basically this allows you to turn thermal throttling on/off for P4 CPU's.

[bigben2k]

Yes, I picked 1.5 rather arbitrarily, in gpm flow rates, in 0.5 increments, for the sake of round numbers, but see below for more

If I was going to be picky, I'd say 1.7 gpm: that where the flow speed in 3/8" tubing still falls under 5 fps, but the drop at that point (over three feet length) is still 11 inches.

The original figure I found was 8 fps, and that was a recomendation as the upper limit, for PVC tubing (source: http://www.ppfahome.org/pdf/pvcpipewaterspec.pdf ). Also: "A flow speed of 5 fps is the guideline for 1 inch ID and higher.". Then, "uncle" Dave reminded me that "This guideline works fine for industrial pumps, but would cause most aquarium style pumps to struggle. Low speed is the weak pump's friend. Save the high speed for where it is needed, and that isn't in the tubing.", and having run the numbers, I've found that 5 fps makes for a pretty good guideline, considering the pressure drops involved.

Otherwise, I'll still stick to my original figure of 1.5 gpm. As most of us know, 1.0 gpm is "typical" of an average loop (ref: the OC article). Any one of us who puts more care in component selection (Johnson pump aside... ) will easily achieve 1.5 gpm and that, IMO, dictates the use of 1/2" ID tubing. Plus, as I've said before, 1/2" fittings are much easier to find locally, so it's really a natural choice.

I agree with pHaestus though: at 3 gpm, the cost of the system becomes unreasonable (aka unjustifiable), but then water cooling itself isn't cost justifiable, unless one can put a price on "peace and quiet".


Back to the evolution of this topic...

Yes, a thicker baseplate gives you more "buffering", for those heat spikes. I particularly enjoyed reading Cathar's figures, on OCAU. Cascade's response time is, relatively, frighteningly low, but should still allow for a thermal protection to kick in. It's still much better than direct die cooling... . It's a trade-off: reduce the baseplate thickness, and depend more on the pump to remain operational, not to cook the CPU.

Has anyone messed with Intel's thermal throttling, to see what temps they can hit?

[BillA]

Ben
when you describe a point on a curve as a limit you will be questioned - and found foolish
and when you persist in defending YOUR value judgments against more accurate descriptions, . . . .

a point on a curve is just that, why not call it such ?
(because then you could not sound like an authority spouting 1.5 or 1.3 or 1.8 infinitum ad nausium ?)
this is the same old re-state and re-phrase stuff you used to do (and I guess wish to continue doing)

no | limits | Ben, just associated incrementally higher 'costs'

[bigben2k]

I hear you Bill.

I'll put together a graph of the pressure drops, for 2', 3' and 4', at 0.5 to 3.0 gpm, for 3/8" and 1/2" ID tubing.

No there is no "set point", it's really down to a design decision. 1.5 gpm is a rough figure I've arrived at, based on the proportion of the pressure drop from the tubing, relative to the total head of the pumps used to achieve those flow rates (reticular implant?).

To qualify my statement, I could compare a few blocks, cores, and pumps, in their various combinations, and present the differences with 3/8 and 1/2". An interesting challenge, but I believe that the wide availability of 1/2" fittings is more important.

Still, might be worth doing...

[BillA]

Originally Posted by bigben2k

I hear you Bill.

I'll put together a graph of the pressure drops, for 2', 3' and 4', at 0.5 to 3.0 gpm, for 3/8" and 1/2" ID tubing.

No there is no "set point", it's really down to a design decision. 1.5 gpm is a rough figure I've arrived at, based on the proportion of the pressure drop from the tubing, relative to the total head of the pumps used to achieve those flow rates (reticular implant?).

To qualify my statement, I could compare a few blocks, cores, and pumps, in their various combinations, and present the differences with 3/8 and 1/2". An interesting challenge, but I believe that the wide availability of 1/2" fittings is more important.

Still, might be worth doing...

shit Ben, doing ANYTHING at all is better than continuously spouting what you think
we look forward to some real data and thoughtful analysis
(finally)

[Corax]

Edit: oops was reading this thread and and another and accidently posted to this one instead of the other one

But I laughed all the way through this article too... OC usualy has much better articles. Too bad he didn't drill through the motherboard! That would have been perfect.

[hdmech]

I NEED to pee Harder/Faster ???

[Butcher]

For hand lapped blocks I doubt you'll see much difference between 600 and 1200+ grit. People have even reported lower temperatures from a mirror finish (theories on this usually involve artic silver's high viscosity causing it to form a barrier layer instead of filling the micro-fine scratches).

[BillA]

"theories on this usually involve artic silver's high viscosity causing it to form a barrier layer instead of filling the micro-fine scratches"

eh ?

so then Sin Etsu would be much worse ?
(retire that 'theory')

[rundymc]

A question on mirror finishes using brasso, autosol and the likes
how do the chemicals accomplish their purpose- by 'filling' the marks on the surface, or by acting as an abrasive?

[Cathar]

Originally Posted by rundymc

A question on mirror finishes using brasso, autosol and the likes
how do the chemicals accomplish their purpose- by 'filling' the marks on the surface, or by acting as an abrasive?

They do so by acting as an abrasive. Brasso contains a superfine abrasive grit suspended in a hydrocarbon/ammonia solution which acts as a "lapping" lubricant. The grit just skims off the top rough layer of the surface and assuming the surface was reasonably flat and smooth prior to starting, will give a shine. When the liquid dries out you're left with grit flakes that just dry out and wipe away.

[Butcher]

Originally Posted by unregistered

"theories on this usually involve artic silver's high viscosity causing it to form a barrier layer instead of filling the micro-fine scratches"

eh ?

so then Sin Etsu would be much worse ?
(retire that 'theory')

I make no claims as to the accuracy of that. I personally tend to lap to 1500 grit and use a method similar to cathar's (looking at something reflected in the surface) to eyeball flatness. It's not hugely accurate, but it's good enough.

[rundymc]

I see, thanks Cathar
so essentially those products aren't terribly effective unless you were to use a process like that used to polish cockpit windshields