DDC-2 Dies

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Originally Posted by Graystar

You definitely have a high heat load, and you’re looking for superior cooling, not just good enough, so I would recommend fitting in as much rad as possible. At the very least you should be able to slap a triple up front and hang a single off the rear 120, right? Like I said, I’m speculating, but I would bet dollars to donuts that a 3 + 1 setup of best-of-class radiators will out-perform your current quad heatercore.

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Done then. Thanks for your help and advice m8! I wish I could get some numbers together to make a comparison, like a before or after. But I am really just figuring out what you guys are talking about. I figure with more reading will come more understanding. By the time I get the new rads (have to wait for Uncle Sam to take a dump), I will have gained a bit more knowledge and be able to garner performance numbers out of my current setup before I make the switch. Would be interesting to know. All I can tell now is my ambient room temps, my idle temps, & and my load temps. This talk about delta's & TAT's and the like is over my head at the moment. But at least with knowing the ambient room temp and the idle\load temps, if I don't learn what the other terms mean and how to get those numbers, these numbers I do know how to get will provide a short insight to any performance\effectiveness gains before and after.

Thanks again Graystar!

Here is my experience. I had a problem where my ddc would stall for no appearant reason on start up. I measured the voltage (12.5 which seems ok). So I took apart my loop and took the pump apart. Appearantly for me it was sticking because of the hydrx had become somewhat solid, as it's been known to do. So I cleaned it out with one of my old cleaning toothbrush and screwed it to a piece of aluminum. It hasn't had a problem for 6 months now.

D5 Ftw!

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Originally Posted by Aldy402

how long were u running it before you died? Im surpised DD didnt send you to swiftech. How did DD handle the RMA process? smooth?

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I had it since 8/2006. DD was very fast to send me the RMA info and Kathi was nice as always.

If you look at the DDC "sticky" you will see my pump with the Alphacool top and the heat sinks on the bottom. I think that I was the first one here to put heat sinks on the bottom. I also have a 120mm Yate D12SL-12 blowing on the heat sinks and the bottom of the pump. There were no chemicals impeding the rotation of the impeller.

I just wish that the Iwaki was 12vdc.

I wish the IWAKI wasn't so huge, sucked so much power, and made so much noise. I have not heard the black IWAKI (MD?) Just the 120 Vold RD's at the aquarium shops and they make a lot of noise. Nice heavy duty looking things though.

IIRC, there was a thread on here a few months back and one theory was that using just distilled water without Pentosin (or equivalent lubricant) resulted in more DDC pump failures and/or starting problems. Although this doesn't make much sense since there are no bearings to lubricate it was supported by a number of people who had pumps fail (using distilled only).

FWIW, I have a pair of DDC-2's running in series and use a 10:1 distilled:Pentosin coolant and haven't had any problems with my pumps in over 6 months of daily start/stops. When I was doing some loop and flow testing with my very first DDC's (purchased from the rumored "bad batch" from PPC's) with tap water only, both stopped running after just a couple of days. :shrug:

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Originally Posted by Chas_The_Man

I wish the IWAKI wasn't so huge, sucked so much power, and made so much noise. I have not heard the black IWAKI (MD?) Just the 120 Vold RD's at the aquarium shops and they make a lot of noise. Nice heavy duty looking things though.

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In other words, you wish you had a DDC! :D

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Originally Posted by virtualrain

FWIW, I have a pair of DDC-2's running in series and use a 10:1 distilled:Pentosin coolant and haven't had any problems with my pumps in over 6 months of daily start/stops. When I was doing some loop and flow testing with my very first DDC's (purchased from the rumored "bad batch" from PPC's) with tap water only, both stopped running after just a couple of days. :shrug:

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Probably rumored bad batch is the one that people run their pumps for the first time without water.

just my 2 cents but petras reporting a 5% failure rate...isnt that huge, i mean 1 in 20 is bad in my mind.and my ddc2 with stock top doesnt get hot top or bottom, a little warm thats it.

Five percent failure is actually terrible. The only problem is, what were the reasons for the 5 percent failure? Was it user error or was it the pump.

@jessethebody and thecoldanddark:

On what data are you basing the opinion that 5% failure rate is bad? My understanding is that a 5% failure rate for consumer electronics is actually very good.

For comparison, PCs have a 15% failure rate in year 1, (http://www.eweek.com/article2/0,1895,1981877,00.asp). Also, Apple claims ipods have a 5% failure rate, which they say is better than average. From my own personal experience, I have returned WAY more than 5% of the electronics I buy for a failure of some sorts.

However, without knowing what the failure rate is for other pumps, I don't know how we can come to any conclusions about whether 5% is good or bad...

fair enough mr.bobsmith .but to all these guys expressing concern about their pump, your odds are 1 in 20 of a dead one. keep that in mind.people were mad about the infamous nvidia 7900 failures which were much less likely to fail than these.

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Originally Posted by Graystar

Lets say that with your OCed processor and two GPUs, you've got a 300-watt heat load. Lets also say that you have poor flow now of 0.5 GPM. That means that the water temperature rises and falls a total of 2.71 C in your loop.

If you plot the DDC+ P-Q curve against the RD-30, and also guesstimate a friction head curve based on 0.5GPM for the DDC, the projected flow rate of the RD-30 would be about double...or 1 GPM. That means that water temperature would rise and fall a total of 1.31 C in your loop.

You have the *potential* to improve temps by 0.655 C (half of half the difference is how it works out.) In truth the improvement is less because your previous lowest-water-temperature will rise slightly by an unknown amount...determined by the performance abilities of the radiator.

Personally, I think you’d do better by getting one of the latest radiators with the thin flat tube design.

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Not true.

Just because you double the flow doesn't mean you double the heat dump, its not a linear curve. Also the rd30's are generally undervolted to rd20 level for best performance. And lastly tests show that, not that I can find any right now, that the performance difference between the undervolted rd30 and dual DDC's is not very significant while reliability is.

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Originally Posted by Quazi

I have been thinking about an Iwaki, but not because of the DDC-2 giving up the ghost for some. Mainly wanting to increase the cooling performance of the Storm if that is possible to do using an Iwaki over a DDC-2 w\Petras Top.

Plus, I leave my rig running 24\7 so an Iwaki would make sense to use if only because they are designed to run all the time for years on end.

So I guess it would boil down to performance. Is there a performance increase in cooler temps using an Iwaki with a Storm Rev. 2? I guess the only real way to know would be to buy one and see for myself. Which I believe I will seeing as I have a little $$$ burning a hole in my wallet. Gotta find one now.

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Iwaki makes a lot of pumps, saying an "iwaki" will give better performance is ludicrous. I was mearly refering to the iwaki RD30 (undervolted around 18v)

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Originally Posted by Quazi

Of course, "the DDC pump employs a brushless DC motor with a lifetime in excess of 50,000 hours when operated at 12 volts — three to four times the life expectancy of other pumps in its class." as quoted from Laings web site. If it get all those hours in, that is somewhere between 6 or 7 years anyway.

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apparently not lol

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Originally Posted by epion2985

Not true.

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Oh yes it is.

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Originally Posted by epion2985

Just because you double the flow doesn't mean you double the heat dump,

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I didn’t double the heat load. The heat load stays exactly the same. That’s why the temperature difference dropped in half.

Did you calculate how much heat is required to change one gallon of water by 2.71 C and two gallons of water by 1.355 C? If you did you’d see that the amount of heat is exactly the same.

I see that I wrote 1.31 C in my post...probably an editing error. It should read 1.355 C.

The heat load always stays the same because it is determined by the operation of the computer, not the cooling system. There is nothing that the cooling system can do to change the heat load. The change in water temperature is dictated by the head load and flow rate. That also is a direct linear relationship. Changes in either always induce linear changes in the other.

What isn’t linear and what isn’t known is at what temperature, above ambient, this entire process of heating and cooling will decide to settle at. That is determined by the efficiency of the waterblock and rad, and how flow rate affects them.

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Originally Posted by Graystar

Oh yes it is.


I didn’t double the heat load. The heat load stays exactly the same. That’s why the temperature difference dropped in half.

Did you calculate how much heat is required to change one gallon of water by 2.71 C and two gallons of water by 1.355 C? If you did you’d see that the amount of heat is exactly the same.

I see that I wrote 1.31 C in my post...probably an editing error. It should read 1.355 C.

The heat load always stays the same because it is determined by the operation of the computer, not the cooling system. There is nothing that the cooling system can do to change the heat load. The change in water temperature is dictated by the head load and flow rate. That also is a direct linear relationship. Changes in either always induce linear changes in the other.

What isn’t linear and what isn’t known is at what temperature, above ambient, this entire process of heating and cooling will decide to settle at. That is determined by the efficiency of the waterblock and rad, and how flow rate affects them.

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mmm no.

Re read what I said. I did not say anything about the heal load. I said heat dump, referring to the heat dumped by the motor of the pump. Which is a function of its power output. As this is the only reason why a bigger pump is not better. And the point I am making is that compared to dual DDC's its not much different. The resulting flow while better is hit by the slightly larger heat dump. In the end dual ddc's perform a little bit better, however the iwaki is more reliable. Thats all.

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Originally Posted by Bobsmith

@jessethebody and thecoldanddark:

On what data are you basing the opinion that 5% failure rate is bad? My understanding is that a 5% failure rate for consumer electronics is actually very good.

For comparison, PCs have a 15% failure rate in year 1, (http://www.eweek.com/article2/0,1895,1981877,00.asp). Also, Apple claims ipods have a 5% failure rate, which they say is better than average. From my own personal experience, I have returned WAY more than 5% of the electronics I buy for a failure of some sorts.

However, without knowing what the failure rate is for other pumps, I don't know how we can come to any conclusions about whether 5% is good or bad...

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Desktops purchased in 2005 and 2006 averaged a 5 percent failure rate in year one and are projected to have 12 percent failure rate in year four. Desktop machines purchased in 2003 and 2004 saw rates of 7 percent in year one and 15 percent in year four.

Remember its 15 percent failure rate for the whole desktop computer in year 4. It's not just one part. It's ram, hard drive, motherboard, videocard, and the psu. If one part goes bad the whole computer is part of that statistic. If you have 1 hard drive, 1 motherboard, a videocard, 1 psu, at least one optical drive, and 2 sticks of memory that could be part of that statistic. So even with your example 5 PERCENT IS TERRIBLE.

Laptops are more prone to failure because of user error and tight spaces with lots of heat. I have seen people walking around with their laptop plugged in, or how about the occasional drop. The average person is terrible at keeping their investment safe.

One more thing I believe the statistic you used was for laptops.

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Originally Posted by jessethebody

just my 2 cents but petras reporting a 5% failure rate...isnt that huge, i mean 1 in 20 is bad in my mind.and my ddc2 with stock top doesnt get hot top or bottom, a little warm thats it.

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I think here is the solution!
I supposed that there are some problems with modded top. Some kind of project mistake, maybe. Here in Italy, usually we use the DDC with the original top, and the percentage of broken pumps is very little.
It will be a good idea to open the poll that you were discussing somewhere, so we can do a statistic.

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Originally Posted by epion2985

Re read what I said. I did not say anything about the heal load. I said heat dump, referring to the heat dumped by the motor of the pump.

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I see. Okay. I’m still right. You’re still wrong.

You’re wrong because there is no pump heat included in my calculations. I didn't include pump heat because the increase in pump heat is a mere 7% of the example heat load (300 watts.) In this case its effects are negligible.

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Originally Posted by epion2985

As this is the only reason why a bigger pump is not better.

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Well this is obviously wrong…otherwise we would all be using pumps from table-top fountains.

If I were to factor pump heat into my calculations, then the change in water temperature increases from 1.355 C degrees to 1.45 C for the Iwaki. That reduced the amount of potential improvement to 0.63 C. So it’s nearly the same. That because the problem isn’t pump heat...the problem is simply the physics of how flow affects temperature.

Increased flow helps only to a point. Beyond that point, increased flow, even if you could do it with no increase in pump heat, will not produce noticeable improvements.

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Originally Posted by thecoldanddark

One more thing I believe the statistic you used was for laptops.

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Rereading the article you are correct. The statistic is for laptops, not desktops.

Regardless, my point is simply that failure rate percentages WITHOUT comparative data are meaningless for making judgments. One cannot simply say 5% is "bad", without a point of reference. For example, if it turned out that all other pumps had a 10% failure rate, then the 5% rate of the DDC would be fantastic. Therefore before saying that the DDC rate is "terrible" (which it very well may be), please provide the comparative failure rate for other pumps.

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Originally Posted by Graystar

I see. Okay. I’m still right. You’re still wrong.

You’re wrong because there is no pump heat included in my calculations. I didn't include pump heat because the increase in pump heat is a mere 7% of the example heat load (300 watts.) In this case its effects are negligible.


Well this is obviously wrong…otherwise we would all be using pumps from table-top fountains.

If I were to factor pump heat into my calculations, then the change in water temperature increases from 1.355 C degrees to 1.45 C for the Iwaki. That reduced the amount of potential improvement to 0.63 C. So it’s nearly the same. That because the problem isn’t pump heat...the problem is simply the physics of how flow affects temperature.

Increased flow helps only to a point. Beyond that point, increased flow, even if you could do it with no increase in pump heat, will not produce noticeable improvements.

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I am not wrong because I am not talking about the same thing as you are. No effect is negligible as I am not talking about what is and isn't as thats a matter of opinion. Niksub here has tried both and to him the difference is not negligible.

I don't see where you are going with desktop fountain pumps, they are tiny not big. We don't use them because they offer very little pumping power.

Again I am not saying the difference in temperature is negligible or not, I know flow benefit is a curve of diminished returns, in fact I am saying what you are saying if you read carefully.

Let me say it again:

Dual DDC's and iwaki rd30 can offer just about the same performance while the rd30 is much more reliable. End of story.

my local reseller got told by laing that startup problems only appear when using an older DDC-2 without an water additive. laing claims to have solved this problems with a new revision, but i don't believe them because supposed to be the "newer" DDCs without the issues are in no way different to the "older ones", they only had a firmware update:stick:

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Originally Posted by epion2985

I am not wrong because I am not talking about the same thing as you are.

I am saying what you are saying if you read carefully.

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I’m confused. First you say that what I had said was not true, then you say we’re not talking about the same thing, and then you say you’re saying what I’m saying.

I can’t make head or tails of it. Lets just agree to disagree...or agree...whichever.

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Originally Posted by generics_user

my local reseller got told by laing that startup problems only appear when using an older DDC-2 without an water additive. laing claims to have solved this problems with a new revision, but i don't believe them because supposed to be the "newer" DDCs without the issues are in no way different to the "older ones", they only had a firmware update:stick:

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In no way different other than new PCB Design, different impeller ?

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Originally Posted by Graystar

I’m confused. First you say that what I had said was not true, then you say we’re not talking about the same thing, and then you say you’re saying what I’m saying.

I can’t make head or tails of it. Lets just agree to disagree...or agree...whichever.

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For the sake of the peace I will admit to have confused myself so just ignore everything I said with exception of this.

"Dual DDC's and iwaki rd30 can offer just about the same performance while the rd30 is much more reliable."

I think we can agree on that.

and let there be peace :)

anyone using Petra coolant...I redid my loop finally and used about 1/3-1/2 shot glass of Petra's coolant in PA160...ran for 8 hrs so far on leak test and seem to be ok

I may add more of Petra's coolant or some Pentosin as well