My micro-channel concept block

[aabtek]

cathar, if your cpu is unlocked, could I persuade you to do a temp test at 1600@1.75V???
I have an asus a7v333 myself with a locked xp1900, and am using a innovatek rev3 with innovarad dual and eheim 1048 .... would love to see how the temps compare with a more extreme setup.

please? (and please state the bios version you use)

[Cathar]

Originally posted by aabtek
cathar, if your cpu is unlocked, could I persuade you to do a temp test at 1600@1.75V???
I have an asus a7v333 myself with a locked xp1900, and am using a innovatek rev3 with innovarad dual and eheim 1048 .... would love to see how the temps compare with a more extreme setup.

please? (and please state the bios version you use)

Hmmm, temperature comparisons over the internet always suck. You simply cannot control the number of variables. Even certain CPU's run hotter than others at the same speed/voltage, and I have two CPUs here that exhibit just this behavior, with one being 2C cooler than the other. Then we have variations in motherboard calibration (they are not calibrated independently), ambient temperature probe accuracy, water temperature probe accuracy, even case temperatures can affect the final CPU temperature as the water block is not the sole source of cooling of the CPU as the CPU does emit a decent quantity of heat through the socket and the case temperature and air-flow impacts how well that is cooled, even on the A7V333.

All of the above can result in a reported temperature varying by 5C or more depending on circumstances. I would be doing neither myself nor yourself a service by allowing a comparison. The values that I get and you get cannot be compared in any meaningful way due to the lack of control over the environments in which those values were achieved in.

[Cathar]

Originally posted by bigben2k
I still think I'll stick with 2mm baseplate. I'm not concerned about it being too thin, because the fins actually act as additional structural support!

I mentionned the thing about higher flow because I thought you said something to that effect over at OCAU. My mistake...

The base-plate can be as thin as you want. It won't bend so long as the top-plate sits flush with the tops of the fins, which is how I have my block.

My view on higher flow-rates is that if you can obtain them easily, then that's nice and good, but I don't believe a block should be design with the intention of selling it, and then requiring a high pressure high-flow pump for it to work, forcing people who bought the block to upgrade their pumps as well. My game is "how much better can we do with the same flow-rate/pressure?"

[aabtek]

Originally posted by Cathar
All of the above can result in a reported temperature varying by 5C or more depending on circumstances. I would be doing neither myself nor yourself a service by allowing a comparison. The values that I get and you get cannot be compared in any meaningful way due to the lack of control over the environments in which those values were achieved in.

yes I know, I wouldn't base any decision on how temps on different setups compared .... but I would still find it interesting to see on-die temps on the same mb with a comparative load ... but if it isn't to bee so be it

[Cathar]

Originally posted by aabtek
yes I know, I wouldn't base any decision on how temps on different setups compared .... but I would still find it interesting to see on-die temps on the same mb with a comparative load ... but if it isn't to bee so be it

Okay, here goes, but as I said, take them with a grain of salt when doing comprisons.

AthlonXP CPU @ 1606MHz, 1.77v (1.75v setting in the BIOS)

Radiator air intake: 21.5C
Water temperature: 23.0C (fans at 7V)

Using BurnK7 (part of the "CPUBurn" suite - I recommend running this - nothing loads the CPU up more - it leaves Sandra for dead).

CPU idle temperature: 26.0C (no CPU idling measures/programs used)
CPU on-die temperature: 29.0C (after 1 hour)

How does that compare?

Edit: Forgot to say - using 1011 BIOS

[bigben2k]

How on earth do you get your water temp down to 23.0?

[Les]

Originally posted by Cathar
Okay, here goes, but as I said, take them with a grain of salt when doing comprisons.

AthlonXP CPU @ 1606MHz, 1.77v (1.75v setting in the BIOS)

Radiator air intake: 21.5C
Water temperature: 23.0C (fans at 7V)

Using BurnK7 (part of the "CPUBurn" suite - I recommend running this - nothing loads the CPU up more - it leaves Sandra for dead).

CPU idle temperature: 26.0C (no CPU idling measures/programs used)
CPU on-die temperature: 29.0C (after 1 hour)

How does that compare?

Edit: Forgot to say - using 1011 BIOS

Interesting.

Showing signs of "Squiffy" behaviour ?( http://forums.overclockers.com.au/sh...5&pagenumber=3
Radiate completely wrong? Calibration wrong?

Would be interested in seing a whole range of mhz and v-core.
I am still at the "Squiffy behaviour" impasse.

[Cathar]

Yes Les,

The C/W non-linearity wasn't lost on me.

Using the ComputerNerd wattage calculator:

1.6GHz/1.77v = 68W
1.925GHz/2.15v = 115W

CPU rise above water temps at full load:

68W = +6C
115W = +18C

Unfortunately the A7V333 doesn't allow me to select sub-1.75v voltages. I know I can run this CPU at 500MHz/1.25v, and I'd love to see if the mobo started reporting CPU temps below ambient.

Could it be that the temperatures reported are "compressed"? Or could it be that the correct temperature is the result of adding 10C to whatever's reported? That'd make more sense assuming the gradient of the thermal probe is accurate. Or could it be a bit of both?

The A7V333 also reports the in-socket diode temperature and it typically sits at 10C higher than the CPU diode. Of course none of this stuff is calibrated properly, but it is good enough to pick up differences.

[Cathar]

Originally posted by bigben2k
How on earth do you get your water temp down to 23.0?

Easy. As stated, 21.5C radiator intake.

...and one of these:



That's an old picture though.

[Les]

Originally posted by Cathar
[B Of course none of this stuff is calibrated properly, but it is good enough to pick up differences. [/b]

Agree.
My current faith is that these "squiffy" temps are real and caused by temp gradients in the die (1sq mm,2W hotspots perhaps?).

[aabtek]

Originally posted by Cathar
Okay, here goes, but as I said, take them with a grain of salt when doing comprisons.

AthlonXP CPU @ 1606MHz, 1.77v (1.75v setting in the BIOS)

Radiator air intake: 21.5C
CPU on-die temperature: 29.0C (after 1 hour)

7.5C above ambient .... I'm at 10C using prime95 ...

thanks for the numbers.

[Cathar]

Originally posted by aabtek
7.5C above ambient .... I'm at 10C using prime95 ...

thanks for the numbers.

Ah, you want Prime95 temperatures. You should've said before.

Radiator Intake Air: 21.0C
Water Temperature: 22.0C
CPU Temperature: 28.0C

Like I said, BurnK7 really puts the heat on just that bit harder.

[bigben2k]

I was just thinking (uh oh!)...

If someone here wants to try to reproduce this kind of cooling, one could take a copper HSF, and add barbs and a lid.

From this list , I found the following were of a copper finned design:
(of course the fin spacing is WAY off, but it's not too bad)

Thermalright SK7

Vantec 1U

Global Win CAK II 38 and CAK II 16

Evercool CUD-725

Dynatron DY1206BH-638

Cho-Liang CB0315U-17

CoolerMaster HSC-V62

Dynatron DC1206BM-R


Now, never mind how they perform as air coolers! BTW, some of these have soldered fins, some have skived fins (fins are shaved off of the copper base). The skived models would probably offer better heat transfer from the baseplate.

(I avoided listing those HSF where the middle fins were removed for the mounting bracket).

[pHaestus]

Originally posted by Cathar

Could it be that the temperatures reported are "compressed"? Or could it be that the correct temperature is the result of adding 10C to whatever's reported? That'd make more sense assuming the gradient of the thermal probe is accurate. Or could it be a bit of both?

The A7V333 also reports the in-socket diode temperature and it typically sits at 10C higher than the CPU diode. Of course none of this stuff is calibrated properly, but it is good enough to pick up differences.

Compression would occur from resistance in the traces. Not uncommon if mobo mfgr crosses pcb layers or runs them too long. 0.4-0.8C per ohm for maxim ics; prolly similar for Asus. Shifting C/W numbers (not constant with watts) is symptomatic of trace lengths being longer than recommended by ic mfgr:

http://phaestus.procooling.com/wirelength.jpg

Would it surprise anyone if there were issues with an Asus onboard temp monitoring device?

[Les]

Originally posted by pHaestus
Compression would occur from resistance in the traces. Not uncommon if mobo mfgr crosses pcb layers or runs them too long. 0.4-0.8C per ohm for maxim ics; prolly similar for Asus. Shifting C/W numbers (not constant with watts) is symptomatic of trace lengths being longer than recommended by ic mfgr:

http://phaestus.procooling.com/wirelength.jpg

I am not certain this is consistent with your view(which I accept) "the temperatures are simply offset by the presence of some resistance in the wires (0.4-0.8C per ohm)".
http://forum.oc-forums.com/vb/showth...threadid=89493

[Cathar]

If the temperatures are offset by 10C as I proposed, this would lead to C/W figures that are consistent (at least for these two data points).

I have a 3rd data point to add to the mix.

CPU @ 1608MHz/1.77v = 69.6W (6C rise above water)
CPU @ 1826MHz/1.87v = 84.1W (10C rise above water)
CPU @ 1925MHz/2.15c = 114.5W (18C rise above water)

Wattages found using the ComputerNerd calculator. Full load done using BurnK7.

Now those values don't make sense, but if we add 10C to each:

16/69.6 = 0.230 C/W
20/84.1 = 0.238 C/W
28/114.5 = 0.244 C/W

Throw in a +/- 0.5C variation on the measured CPU temps and it all falls into line (more or less) within expected behavior.

I'd say for this particular motherboard I own, I may as well bump the CPU die temperature compensation by +10C and I'd probably be pretty close to the mark.

Interesting too, as 0.23-0.25 C/W values would come close to fitting it with Les's hypothesised C/W values for the block itself + the ~0.15C/W for the thermal paste barrier.

[Les]

Originally posted by Cathar
If the temperatures are offset by 10C as I proposed, this would lead to C/W figures that are consistent (at least for these two data points)..............................

Taken the liberty:



Yes, so far looks like "offset" and not "squiff".
Would love to see some 66 fsb which is where I encounter the anomaly

[Cathar]

Okay, here's an additional data point.

CPU @ 706MHz/1.79v = xxxW (1.0C rise above ambient)

Okay, here's where I think the ComputerNerd calculator falls down. It reports 37.7W. I think it's wrong.

Looking at AMD AthlonXP specifications, we see a 12W rise over a 400MHz range @ 1.75v between 1333MHz and 1733MHz. At 1333MHz AMD lists 60W. If we apply this same gradient we find a 19W difference at 700MHz at 1.75v, for a 41W value. Compensate for the increased voltage and we arrive at around 43W.

Throw in our 10C compensation and we get:

11/43 = 0.256 C/W.

With all the reported mess here at this level this seems quite reasonable and still fits in within the margins of error.

[Les]

Cathar
Thanks for additional data - the more the merrier.
There is surprisingly little presented over a range of mhz and v-core - maybe shows up too many anomalies.
As you rightly indicate it can become "messy" and have not updated plot with last data point.
Maybe a range of MHz at const V-core and range of v-core at const mhz would be enlightening .
Have dug up one limited set of results:

[Cathar]

I just picked up a Pondmaster-4200 pump, which is still pushing 4m of head at 1000lph. Just turned it on outside with the 1/2" OD nozzle pointing upwards and the water fountain shot about 2.5m straight up.