Go Back   Overclock3D Forums > [OC3D] General Forums > OC3D Reviews & Videos
Reply
 
Thread Tools Display Modes
 
  #11  
Old 22-05-07, 03:29 AM
PV5150 PV5150 is offline
OC3D Elite
 
Join Date: Mar 2005
Posts: 9,934
Quote:
Originally Posted by Allsorts
Ooh ooh I've been waiting patiently for this shootout, thanks Peevs!

Laing recently made some minor updates to the DDC pump and PTS followed suit with their DDCT-01s top. If I had held off for a few months I would have the new versions.
Thanks for the additional info mate...very much appreciated - Reps. Glad you liked the review too

__________________
Quote:
Originally Posted by name='Jim'
"Jonathan 'Fatal1ty' Wendel may be 12-time world gaming champ, but how does he cope inside a 50c hot box sucking on a heavy load?":rocker::rocker:
Reply With Quote
  #12  
Old 22-05-07, 07:14 PM
Rob* Rob* is offline
Advanced Member
 
Join Date: Feb 2007
Posts: 272
Good job well done i think Matt thanks for completing the "pump off" for us

Soon we'll be sending over 3 more contenders for you to put against/with those results.. I'm not aloud to say which 3 as they are all work in progress tops but rest assured OC3D will be the first to know how good they are!

On a side note, adding to what Allsorts said regarding the new DDCT-01s from Petra's Tech.. The only real difference is the inside housing where the Impeller sits. Someone at Laing somewhere down the line decided to give the new European DDC a larger (Blue) impeller rather than the USA (Black) slimline impeller and on the PTS top there is a little 2mm lip on the underneath side which fouled on the new Impeller, hence the need to make a new top without this lip and slight improved performance while they did the revision.
Reply With Quote
  #13  
Old 22-05-07, 08:50 PM
Petra Petra is offline
Newbie
 
Join Date: May 2007
Posts: 2
Hey everyone! First post here...but you already know who I am

Anyway, that review was a nice start; however, I would have liked to see performance curves <--link... because that would have provided a much more accurate indication of the performance characteristics that each top provides. As it stands, you're only seeing a few pieces of the puzzle which, really, doesn't tell you very much--each top is going to have its own "sweet spot" within the pump's operational range. That said, there are a few things worth pointing out here (keep in mind, this is supposed to be constructive criticism):

- According to your own results, the DDCT-01s performed better than the Alphacool top on the 18W DDC-3.2, despite having slightly lower head pressure--this is important with regard to what I said above (this is a performance curve thing... if one can manage to kick the curve outward within the pump's most useful pressure range, then the flowrate will be higher despite having lower static head. The rough curve that I did for the RD-30 at 18.1V is a perfect example of this [see above link]). For reference, my original testing, comparing my prototype to the Alphacool top, was done using an 18W DDC-2 (different pump, slightly different results, same story nonetheless).

- All of your static head numbers for the DDC-3.2 appear to be low (33kPa =~4.8psig...should have been closer to 5.6psig). However, because all of the tops were tested in the same manner, this really doesn't matter much (absolute standpoint, you're off... relative standpoint, you're fine). There are several things which could have let to this, that I can think of ATM: low voltage (which, since I'm assuming that you were monitoring it, shouldn't be an issue), a wonky pump (some performance variation has been known to exist with these pumps--not sure how much this applies to the DDC-3 series, though), your pressure gauge (and measuring point), etc. I don't have numbers for the DDC-3.1, so I really can't comment there (though the odd result is making me want to bust out the test setup again to see what's up... ).

- Since you already had a pressure gauge in the test setup, your "max. flowrate" data should have been represented as flow at a given pressure because, from your data, I'd estimate that your test setup was incurring a pressure drop of between 2.5psig and 3psig at 2.93 Gal/min (11.1 l/min)... same goes for your 'in loop' test (because it looks as if you were incurring about a 5psig drop in that test...and a lot of that was likely your flowmeter).

- You didn't include the stock top as a control (this would have also acted as an indication of absolute accuracy).

The DDCT-01s got its ass kicked on the 9W DDC-3.1... yeah, I kinda figured that would happen. Though, in my defense, I'm not designing for the 9W DDC (DDC-1 or DDC-3.1). Granted, I can't fully explain that large of a performance discrepancy right now...it's somewhat perplexing.

Overall, a decent review... but, as with all reviews, there's always room for improvement. The more you can teach someone with a review, the better.

Quote:
Originally Posted by name='WaterCoolingUK'
On a side note, adding to what Allsorts said regarding the new DDCT-01s from Petra's Tech.. The only real difference is the inside housing where the Impeller sits. Someone at Laing somewhere down the line decided to give the new European DDC a larger (Blue) impeller rather than the USA (Black) slimline impeller and on the PTS top there is a little 2mm lip on the underneath side which fouled on the new Impeller, hence the need to make a new top without this lip and slight improved performance while they did the revision.
Close, but.... The removal of the inlet ring had to be done because they shrunk the diameter of the impeller's inlet (which the ring was originally designed to fit within) and they did a heck of a lot more than just that. Take a look at my most recent testing thread in XS (HERE <--link), you'll see the rather large performance difference between the 18W DDC-3.2 and the older 18W DDC-2 that's a result of the new motor.
Reply With Quote
  #14  
Old 22-05-07, 10:14 PM
Rob* Rob* is offline
Advanced Member
 
Join Date: Feb 2007
Posts: 272
Quote:
Close, but.... The removal of the inlet ring had to be done because they shrunk the diameter of the impeller's inlet (which the ring was originally designed to fit within) and they did a heck of a lot more than just that. Take a look at my most recent testing thread in XS (HERE <--link), you'll see the rather large performance difference between the 18W DDC-3.2 and the older 18W DDC-2 that's a result of the new motor.
Aye not far off

Welcome Alex, i was kinda expecting a technical post from you on this review..

To say the least i was shocked that the Alpha top took the lead for the most part and i also did expect the OCL top to do much better but life is full of suprises! This is one of the main reasons we had the test comparison done. So when you make your spanking new DDCT-02! we can send it off again as i said above and have one big ass list of tops and how they perform

Keep up the good work guys
Reply With Quote
  #15  
Old 22-05-07, 10:52 PM
FarFarAway FarFarAway is offline
Newbie
 
Join Date: Mar 2005
Posts: 0
Hi there Petra (or Alex )

Thanks for your comments.

I will leave Matthew to comment on the points you have made, but we do appreciate your expert feedback and you are quite right a review can always be improved.

Matthew is in Australia so he will reply whenever their topsy-turvy time is over there, but I am sure as always he will take the points on board.

As you say there are some issues with the methodology, but I am 100% confident that we have produced a fair and non-bias review in this, as in all reviews we do here at Overclock3D.

Anyway welcome to the forum and I hope we will see you around...possibly for round two!
Reply With Quote
  #16  
Old 22-05-07, 11:11 PM
PV5150 PV5150 is offline
OC3D Elite
 
Join Date: Mar 2005
Posts: 9,934
Quote:
Originally Posted by name='Petra'
Hey everyone! First post here...but you already know who I am

Anyway, that review was a nice start; however, I would have liked to see performance curves <--link... because that would have provided a much more accurate indication of the performance characteristics that each top provides. As it stands, you're only seeing a few pieces of the puzzle which, really, doesn't tell you very much--each top is going to have its own "sweet spot" within the pump's operational range. That said, there are a few things worth pointing out here (keep in mind, this is supposed to be constructive criticism):
Hi Petra and welcome to OC3D. Thank you for your constructive criticism on my review. I agree that performance curves would have made added credibility and validity to the results, and they shall be included for the next round.

Quote:
According to your own results, the DDCT-01s performed better than the Alphacool top on the 18W DDC-3.2, despite having slightly lower head pressure--this is important with regard to what I said above (this is a performance curve thing... if one can manage to kick the curve outward within the pump's most useful pressure range, then the flowrate will be higher despite having lower static head. The rough curve that I did for the RD-30 at 18.1V is a perfect example of this [see above link]). For reference, my original testing, comparing my prototype to the Alphacool top, was done using an 18W DDC-2 (different pump, slightly different results, same story nonetheless).
Understood.

Quote:
All of your static head numbers for the DDC-3.2 appear to be low (33kPa =~4.8psig...should have been closer to 5.6psig). However, because all of the tops were tested in the same manner, this really doesn't matter much (absolute standpoint, you're off... relative standpoint, you're fine). There are several things which could have let to this, that I can think of ATM: low voltage (which, since I'm assuming that you were monitoring it, shouldn't be an issue), a wonky pump (some performance variation has been known to exist with these pumps--not sure how much this applies to the DDC-3 series, though), your pressure gauge (and measuring point), etc. I don't have numbers for the DDC-3.1, so I really can't comment there (though the odd result is making me want to bust out the test setup again to see what's up... ).
Yes I felt that the results given were a little low, but considering that the same method and gauge were used for the review it was relative. Further, here in Queensland the average kPa for household mains water pressure (shower outlet for example) is around 45-50 kPa, so in the grand scheme of things 36 kPa from a small 12V pump is respectable, relatively speaking.

As far as significant head pressure drop, I agree that it it may have been the pressure gauge. I would actually have liked to find one with a finer gradient on the dial personally, but was unable to find any here in Aus in time for the review.

You speak of a 'wonky pump'...a couple of times during the review I experienced what can only be described as a cavitational effect, where the stator sounded as if it were off-balance and not receiving ample fluid. A couple of re-seats seemed to eliminate the phenomena

Quote:
Since you already had a pressure gauge in the test setup, your "max. flowrate" data should have been represented as flow at a given pressure because, from your data, I'd estimate that your test setup was incurring a pressure drop of between 2.5psig and 3psig at 2.93 Gal/min (11.1 l/min)... same goes for your 'in loop' test (because it looks as if you were incurring about a 5psig drop in that test...and a lot of that was likely your flowmeter).
Agreed, the flowmeter would have hurt flow. But, I went the flowmeter route for the reason that it gives an accurate measurement of the volume of water that has passed through the loop. Granted though, it would have hurt flow performance.

Quote:
You didn't include the stock top as a control (this would have also acted as an indication of absolute accuracy).
Yes I should have done, and it was my initial intention to have it included. I was waiting on some 3/8" barbs to arrive as I only had 1/2" ones here. My bad!

Quote:
The DDCT-01s got its ass kicked on the 9W DDC-3.1... yeah, I kinda figured that would happen. Though, in my defense, I'm not designing for the 9W DDC (DDC-1 or DDC-3.1). Granted, I can't fully explain that large of a performance discrepancy right now...it's somewhat perplexing.
Again, I would have thought that it would have performed better too. But, the DDC-01s is obviously better suited and optimised for the more powerful DDC Ultra.

Quote:
Overall, a decent review... but, as with all reviews, there's always room for improvement. The more you can teach someone with a review, the better.
Thank you for the feedback/constructive criticism, it is very much appreciated. I'm still learning to make my reviews as accurate and so what you have suggested here today has been taken onboard.

PV
__________________
Quote:
Originally Posted by name='Jim'
"Jonathan 'Fatal1ty' Wendel may be 12-time world gaming champ, but how does he cope inside a 50c hot box sucking on a heavy load?":rocker::rocker:
Reply With Quote
  #17  
Old 23-05-07, 11:12 PM
Devolution Devolution is offline
Newbie
 
Join Date: May 2007
Posts: 1
Congratulations PV5150 on a very informative test sequence. It looks like the

review has stirred a bit of interest from one of the product manufacturers.

Quote:
Originally Posted by name='Petra'
Hey everyone! First post here...but you already know who I am
I think so.

Quote:
Originally Posted by name='Petra'

Anyway, that review was a nice start; however, I would have liked to see performance curves <--link... because that would have provided a much more accurate indication of the performance characteristics that each top provides. As it stands, you're only seeing a few pieces of the puzzle which, really, doesn't tell you very much--each top is going to have its own "sweet spot" within the pump's operational range.
Perhaps you can tell me why you did not include pump performance curves in your own pump head testing presented here on XS.

http://www.xtremesystems.org/forums/...d.php?t=117215

Quote:
Originally Posted by name='Petra'
That said, there are a few things worth pointing out here (keep in mind, this is supposed to be constructive criticism):
I am always concerned that a manufacturer who feels the need to comment on reviews will have their "constructive criticism" interpreted as an attempt to diminish the relevance or findings of a reviewer or the reviewers technical capacity.

Having said all that I think that there should be more testing of the various tops carried out now that a new range of DDC pumps with the blue impeller have been released. Again congratulations on a well thought out review. I look forward to the follow up.
Reply With Quote
  #18  
Old 24-05-07, 12:35 AM
Petra Petra is offline
Newbie
 
Join Date: May 2007
Posts: 2
Quote:
Originally Posted by name='Devolution'
Perhaps you can tell me why you did not include pump performance curves in your own pump head testing presented here on XS.

http://www.xtremesystems.org/forums/...d.php?t=117215
Simple, really... That was my initial round of testing which was carried out before I was equipped to do performance curves (much like PV). If you check my latest testing thread ( http://www.xtremesystems.org/forums/...d.php?t=137484 ) you'll find performance curves of my own tops and a rough curve for an RD-30 at 18.1V. The reason that other tops weren't included in that testing was because I was primarily interested in the performance changes going from the DDCT-01 to the 01s and how the new DDC-3.2 compared to the DDC-2. At the time, I was also performing testing on other top prototypes as well as unrelated pump testing for a couple OEM's that I work with and didn't have the extra time to spend (easily two hours per top per configuration, not counting setup and analysis) testing more tops/configurations.

If anything, when I published it, I was hoping that people would look at my initial round of testing and realize that, so long as you aren't taking heat dump into consideration, it really doesn't matter which of the commonly available pumps you buy--they'll all perform within about 0.6 (low drop)-0.2 (high drop) Gal/min of each other, depending on the pressure drop incurred by the components used. As anyone who is familiar with controlled water cooling component testing will tell you, once you're over 1 Gal/min, that flow difference really isn't going to make much of an appreciable difference in overall cooling system performance. Now, take heat dump into consideration and things change a bit...but I'm beginning to get way off track here.

Quote:
I am always concerned that a manufacturer who feels the need to comment on reviews will have their "constructive criticism" interpreted as an attempt to diminish the relevance or findings of a reviewer or the reviewers technical capacity.
Therefore nobody should ever offer up any sort of criticism/thoughts/suggestions, regardless of intent, and everybody's opinions are equally valid, no? Pffft... the wonders of relativism

Look, I tend to knock most tech sites pretty hard--let's face it, the testing methodologies of most are absolutely atrocious and are aimed solely at pandering to manufacturers. Here, on the other hand, I see a reviewer who is actually attempting to do something right and I'd like to see that continued and improved upon. The more useful, solid data that we (the members of the water cooling community) have to work with, the better (hence the offering of any assistance that may be desired to aide in this effort, and the comments that I made).

Competition is good, competition breeds innovation... it is the job of a tech site, however, to educate its readers well enough to properly recognize said innovation and what it means to them. Because, as I mentioned on XS, I think that a review should be educational as well as informative because, sadly, not everyone is going to understand what's going on once you start throwing performance curves around and discussing the relation between head pressure, flow rate, and component-induced pressure drop.
Reply With Quote
  #19  
Old 24-05-07, 01:06 AM
FragTek's Avatar
FragTek FragTek is offline
OC3D Elite
 
Join Date: Mar 2005
Location: Stafford, VA USA
Posts: 15,931
Send a message via AIM to FragTek Send a message via MSN to FragTek Send a message via Yahoo to FragTek
Petra 1

Devolution 0

__________________
Reply With Quote
  #20  
Old 24-05-07, 09:05 AM
FarFarAway FarFarAway is offline
Newbie
 
Join Date: Mar 2005
Posts: 0
Personally and quite frankly I believe the review to be a fair representation of what happened when the pumps were tested and as an independent review site we are quite happy that we successfully represented the pumps performance.

Yes in every review there are bound to be things that could have been changed methodology wise, but the same is to be said with any review and at least we have no bias on preference and so can take a standpoint of professionalism and impartiality.

So I thank-you for your comments and we will certainly take them on board, but the results are the results and that is a part of our integrity and I will not have the review amended or changed as far as they are concerned

Well done Matthew, a stirling job as usual.
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump






All times are GMT. The time now is 01:09 PM.
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.