Informal test results CPU 350 vs Apogee GTZ

[nikhsub1]

Let me say this one more time for the cheap seats....What I personally like to see is real world tests only. The reason behind that is simple...you get to see real world results.

And here lies my disagreement with you. It is always best to ISOLATE the part that you are testing, remove as many variables as possible. You say just the opposite, you would like testing done with all the variables in the world. This makes for bad data. Ever heard of the word 'GIGO'?

[hellcamino]

And here lies my disagreement with you. It is always best to ISOLATE the part that you are testing, remove as many variables as possible. You say just the opposite, you would like testing done with all the variables in the world. This makes for bad data. Ever heard of the word 'GIGO'?

Yeah I'm familiar with the term garbage in garbage out.

I really do understand the idea behind isolated testing but I feel end users would be better served by real world testing. As it sounds that Gabe has a very elaborate lab it just doesn't sound too difficult to me to use standard water cooling gear for at least a secondary test. I would think it would even be in Gabe's interest to do so!

By standard gear in Gabe's case I mean using a mcp355, mcres, GTZ and an MCR320. I would think it would be a real selling point for him (and useful info for everyone) to run a test (in this case) with both blocks then add an MCW30 to the nb and run it again. I am betting that it would just about be a toss-up on the first test and the GTZ would slaughter the koolance block in the second. As many people like to run cpu-nb loops I would think that would be one hell of a demonstrative test in his favor and untainted.

Would that not make for a solid test for you as well?

[[XC] riptide]

Hellcamino.... you made your point about wanting more tests. Thats fine. Gabe has eyes and he'll read them and maybe he might. Maybe he won't. The tests done are exactly what some of us wanted, so that we isolated the block. Its one thing to say you want more tests, its another to discredit the ones done. Any more *attempting* discrediting and we'll consider it trolling.

[gabe]

Been uber busy all week working on major project, and I am shocked to see this thread reached 7 pages already.

Still working hard, and too busy to respond individually, it would take hours! Here is some additional info.

Stephen told me that he ran the chiller pump on full because he noticed how restrictive the 350 was, and he wanted to keep his measurements out of the asymptotic area of the curve (0-0.5 GPM - see for example http://www.swiftech.com/assets/image...e-TR_VS_FR.PNG). He likes to take his temp measurements in the "flat" area.

For comparative testing, it is not practical to try to reproduce a user environment with the chiller, because the PQ curve of our pump is too different from that of commonly used pumps (655, 350's etc). Knowing that we need to eliminate the single biggest variable by keeping the coolant temp constant, one needs to understand that if we wanted to mimic a user setup fairly in a comparative test, we'd have to measure the flow with an arbitrarily chosen loop setup, then disassemble the block, and match the flow on the chiller, then do that again for another block, then adjust the chiller pump again, etc.. it's simply too time consuming.

[T_Flight]

Absolutely. I'm gonna be one pissed off individual if this forum gets overrun by garbage tests, and the people that do real scientiffic method testing stop posting these tests.

Tests with all kinds of variables thrown in there are meaningless. For the folks who do these tests, please continue, and ignore the naysayers. Don't let them win and destroy this forum. I've seen some of the most talented folks just get to the point of not caring anymore, and I get furious when I see that. What can we do to stop this? That information is too valuable to let it slip away because of naysayers and trolling. Name it.

I don't wanna see these guys that have worked their tails off to build these labs and that do these tests get ran off by this trolling. Let me know what I can do...just name it, and I'll do it.

[gabe]

I think you don't understand. They have an industrial pump (similar in specs to an Iwaki MD-30Z IIRC) that they can vary the flowrate with valves... the water is kept at a constant temp. Your comments are irrelevant.

Gabe it would be interesting to see the GTZ at 1.33GPM as well... I realize the 350 is way more restrictive but still.

see http://www.xtremesystems.org/forums/...&postcount=162

[gabe]

How much worst? That Is what I’m curious about? ~1.5C temp difference at whatever Gabe’s flow rate was set at the pump. I want to know how much difference would it make with D5 or DDC 3.2’s pumping power. Therefore I can base my judgment whether the temp difference is negligible or not. Like Webby mentioned we won’t know until it is tested.

see http://www.xtremesystems.org/forums/...&postcount=162 and take a look at the example of curve you will understand quickly!

[gabe]

It has been a bit entertaining and frankly I'm probably pushing too hard. I tend to get overly passionate about things like this and I should probably back off a bit

So, in the interest of fairness and all that, I have a suggestion that I think might resolve the issue and make Gabe's tests more valid.

I suggest that the tests be conducted like this. First, take the GTZ block and install and test as Gabe mentioned. The key here is to find the BEST temperature possible with the same load and same water temperature by only varying the water flow. In other words change the water flow over time, pausing at various steps and observing the resulting temperature, until you find the absolute lowest you can get.

Next repeat the test for the CPU-350. Keep all test conditions the same except vary the flow rate until you obtain the absolute lowest temperature for the Koolance block.

If the theory is right you might have a best low temp for each block at varying speeds/flow for the pump. If true it might indicate that each blocks "sweet spot" is different, so choosing one over the other may depend on the type of pump, or flow rate, you plan on using.

Of course we may see that one block is always lower across all flow rates. If true then great, we have a king. But I think it's too early to tell that.

Sound reasonable?

please read: http://www.xtremesystems.org/forums/...&postcount=162 it explains how difficult what you are asking for is.

[gabe]

Your point is valid, your math is not. What if you reduce the gpm on the gtz to 1 , cant just shave of 1gpm. The flow rate would probably be just above 1gpm for the 350.

if you set the flow rate of GTZ to 1GPM, and use the chiller's pump at same setting to test the 350, flow will be higher in the 350 due to chiller's pump PQ. please read: http://www.xtremesystems.org/forums/...&postcount=162 it explains how time consumming it would be to do that fairly in the context of regular W/C pumps.

[gabe]

too bad you are in MN Skinnee, We'd be delighted to have you visit our lab.

[skinnee]

Thanks gabe! I will take you up on that lab visit when I am out in CA. I have a feeling that before this time next year I will over on the west coast for a few days.

[santiagodraco]

see http://www.xtremesystems.org/forums/...&postcount=162

Well, then eliminate the chiller all together and use a radiator. I'm sure your lab has a good constant room temperature.

[anzial]

lols, it never ends, huh?

[sirheck]

Easy killers!
In this test the only variable is the CPU block.
Restriction difference for just about any type of pump used
should be proportional.

[santiagodraco]

Let me ask the question a different way (and I may be misunderstanding Gabe's reply (the one he's linked).

It seems that by using the chiller certain testing peculiarities are introduced that would make the use of a "normal" pump inappropriate in some way (correct Gabe?). If that is the case, and the use of the chiller is to eliminate the variable of room temperature (another assumption on my part) then if we assume the room temperature is very constant (maybe not) wouldn't the use of a radiator eliminate that and allow the use of a readily available pump?

I guess what I'm getting at is the good old real world test scenario. All roads seem to lead back to the beginning

But let me say this. I'm not saying Gabe's tests don't have merit (and yes I am very aware of what the scientific method is and variables) but... I just can't seem to get it out of my mind that the lab you use Gabe seems to introduce it's own set of variables that might not be representative. Maybe I'm completely off base, and I can't quantify them well, it's just a feeling (and yeah feelings aren't very scientific )

[MpG]

Any sort of extended testing will dump heat into the room, which will slowly raise the ambient temperature. It's almost impossible to avoid this - if you look at some of Martin's testing outlines, you'll notice that he actually used an AC unit to keep ambients steady, but even his testing had an ambient range of several degrees, courtesy of the AC kicking on and off. Really, what a chiller does is exactly what the AC would do under ideal circumstances, and the chiller can do it without having to worry about variables such as air circulation in the room, or what path the radiator exhaust takes.

[Martinm210]

I would second Niksub1's suggestion (originally Cathar's idea) in plotting c/w relative to "Hydraulic Pumping Power". This would be a easy way to completely eliminate the pumping power variable as you would clearly see the relative performance differences between both blocks and they wouldn't be a great representation of performance. C/w vs Flow rate skews the results to make more restrictive blocks appear better, however if you use hydraulic horsepower it's comparing a straight thermal performance relative to pumping power.

Thanks for testing, very nice

[[XC] riptide]

I removed 3 posts that were made after my last post. If you don't understand why the test was done with a temp controlling chiller you don't belong in the thread and are trolling. Anymore trolling will get infractions.

[gzipper]

Been uber busy all week working on major project, and I am shocked to see this thread reached 7 pages already.

Still working hard, and too busy to respond individually, it would take hours! Here is some additional info.

Stephen told me that he ran the chiller pump on full because he noticed how restrictive the 350 was, and he wanted to keep his measurements out of the asymptotic area of the curve (0-0.5 GPM - see for example http://www.swiftech.com/assets/image...e-TR_VS_FR.PNG). He likes to take his temp measurements in the "flat" area.

For comparative testing, it is not practical to try to reproduce a user environment with the chiller, because the PQ curve of our pump is too different from that of commonly used pumps (655, 350's etc). Knowing that we need to eliminate the single biggest variable by keeping the coolant temp constant, one needs to understand that if we wanted to mimic a user setup fairly in a comparative test, we'd have to measure the flow with an arbitrarily chosen loop setup, then disassemble the block, and match the flow on the chiller, then do that again for another block, then adjust the chiller pump again, etc.. it's simply too time consuming.

But if you got the pressure drop over the block you could match that with the formula:
dP=rkQ^2 => k=dP/(rQ^2) ,(k=l/2) r=density of water Q=flow.
you could plot that into a PQ chart of a "regular" pump and figure out the flow through it (without tubes and tubes have low k). K is the same with any pump assuming non-laminar flow.
Then alot of these discussions wouldnt be necessary.

The testing by itself is very good.

[SiGfever]

Let me ask the question a different way (and I may be misunderstanding Gabe's reply (the one he's linked).

It seems that by using the chiller certain testing peculiarities are introduced that would make the use of a "normal" pump inappropriate in some way (correct Gabe?). If that is the case, and the use of the chiller is to eliminate the variable of room temperature (another assumption on my part) then if we assume the room temperature is very constant (maybe not) wouldn't the use of a radiator eliminate that and allow the use of a readily available pump?

I guess what I'm getting at is the good old real world test scenario. All roads seem to lead back to the beginning

But let me say this. I'm not saying Gabe's tests don't have merit (and yes I am very aware of what the scientific method is and variables) but... I just can't seem to get it out of my mind that the lab you use Gabe seems to introduce it's own set of variables that might not be representative. Maybe I'm completely off base, and I can't quantify them well, it's just a feeling (and yeah feelings aren't very scientific )

Even with a very well controlled air conditioning system you have 1-1.5F difference in the room temperature if not larger swings. Since our radiators rely on the room temperature for their heat transfer the differences between test can vary substantially.

But with a chiller holding the water temps to tenths of a degree you have the best constant between test. (This statement is not directed at any one person) Questioning to understand someone's test results is good for learning but questioning someone's methods unless you are more qualified to do the testing is just foolish.

If this kind of thread craping continues manufactures and independent testers will not want to share their results, who would. To spend the kind of time and money to do valid testing to only have unqualified people call them everything from a liar to a fool is not what this forum was built on. FUGGER pays large sums of money to keep this forum running so all of us have a place to share our passions and ideas so lets bring XtremeSystems back to the fair and balanced forum it is known for. just my $.015

[T_Flight]

riptide already said it wasn't gonna continue, and I am glad. Sig, that last paragraph you wrote could not have been written any better. It ought to be put into it's own locked sticky at the top of this forum.

Man, I've been to other forums, and some of the stuff I read there had me believing some very bad things. Things which I later learned on here were completely false and inaccurate. That is why I registered here in the beginning and is why I am here now. These scientiffic tests are what separates the fact from fiction. If we started arbitarily thorwing in just anything into the mix we'd have contradictory results and tests and it would be a mess.