3/8 vs 1/2 inch Tubing, is bigger better?

So I just got my Maximum PC April issue where they talk about water cooling. One part of the test they talk about tubing size. Quoting the article, "Tubing is everything, 3/8-inch-diameter tubes spiked our temperatures on 100 percent CPU use to an average of 81 C and a maximum of 83.5 C. The same cooling setup using 1/2-inch tubing hit an average of 73 C with a maximum of 75.25 C. The more fluid you can move over your heat exchanger, the cooler the average temperature that fluid will be that's why 1/2 inch tubing wins."

I didn't think that made such a big difference but 8 C is quite a bit considering that a if a CPU block was 8 C better everyone would use it over another. You will have to read the article to see the test equipment. What do you guys think about it? Should I use 1/2 over 3/8 inch? I already have 3/8 tubing and barbs. :confused:

The differences assuming 10ft of tubing between 3/8" and 1/2" should not account for more than about 0.2C at most if you're over 1GPM.

You would have to be in the .4 to .6GPM range to start seeing differences that large and that is simply hard to do with any of your common good pumps.

Are they using a H50 pump?...:)

There was a test on tubing size done by someone - I don't remember who exactly (skennee probably) and the difference was minimal.

Cathar's test says otherwise, but I guess it depends on more than just the tube size.

For example, when the magazine guys changed tubing on their setup, did they remove the blocks and reapply TIM? TIM done badly can easily account for 5-6 degrees.
Did they do both tests in the same ambient temperature? Could vary by 4-5 degrees if it's a common household, I guess?
Perhaps their 3/8 tubing needed more 90 fittings in order not to kink? Perhaps when they installed 3/8 it WAS kinked, and they just didn't know it mattered much?

Apparently they used a MCP655 for their "custom" build. I didn't think it mattered as much as they say.

The "Other" piece that's missing at least in the estimator and pretty much any pressure drop is the effects of 3/8" barbs. While the tubing may not have much restriction, the barbs and elbows of smaller sizes probably add up to even more restriction. I still don't see how it could be that much completely because of tubing size alone.

I suppose it also depends on the CPU block used, some of the older "Large Channel" blocks were much more sensitive to flow rate than your typical .3mm microfin type block from today's latest design. I have an old "Stinger V8" that was one such block....it LOVES high flow, but it pretty much relied on a nozzle to do the work and had little to no pin/fin heat transfer.

Anyhow, I suspect it's ambient or other testing error. Unless you are running 100' of tubing or small 3/8" barbs, 3/8" tubing will not be worth 7C over 1/2"....just not possible for your typical system.

First and foremost, let's begin with the source.:rolleyes:

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Originally Posted by Feklar

Apparently they used a MCP655 for their "custom" build. I didn't think it mattered as much as they say.

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I have seen people "Mistake" the arrow direction on the vario. If they were accidentally running at setting 1 instead of 5...I could see a big difference there. Setting 1 and 2 are REALLY low in pump power. You would be probably in the .5GPM range.

I agree, something is amiss with their test to account for such a large difference. If you don't have a lot of water cooling experience and read the article it makes you second guess your choice in equipment unless you get other opinions.

All I can say is "That poor, poor cat".

Yea I called my wife from work on Valentine's Day and told her to get the kitty ready. When I came home she did that to the cat.

Hmmmmm, this is a tough one. What would be the optimal tube size to use in your "cooling" loop? Either the smaller more restrictive size, or a larger less restrictive size? :eh:

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Originally Posted by SlowSVT

Hmmmmm, this is a tough one. What would be the optimal tube size to use in your "cooling" loop? Either the smaller more restrictive size, or a larger less restrictive size? :eh:

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Did you read the replies offered thus far? :rofl:

The last place I would get water cooling advice is maximum pc

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I get Maximum PC and like the magazine, but they really should do a bit more homework before they publish stuff like this claiming a 10c difference.

I personally think that we should all just go ahead and use 1" tubing. That should net us at least a 20c reduction in temps, right?

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Originally Posted by voigts

I personally think that we should all just go ahead and use 1" tubing. That should net us at least a 20c reduction in temps, right?

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You're still using tubes measured in inches? Pft, what a noob, 1/2 foot diameter is where it's at!

;)

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Originally Posted by theseeker

First and foremost, let's begin with the source.:rolleyes:

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Originally Posted by Aaronharmon

The last place I would get water cooling advice is maximum pc

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^This...+1^

meh tubing size is all moot once u get to 3/8ths.

I mean from 1/8 to 1/4 you will see a difference, but once u get to 3/8ths it all changes.

The reason for 3/8ths in reality was the thicker wall they brought.
This helped us a lot for bends b4 we had 90's and other adaptors.

Also it helped a lot in getting South Bridge, and SLI cards b4 we had options for that.


The biggest lesson to learn is, if your going 3/8ths, you need to stay with 3/8ths otherwise cost will rise because of the requirement of different tubing.
and with the availability of options on our end now in fittings, you really dont require that thicker wall for bends. You just use an adapter.

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Originally Posted by antiacid

You're still using tubes measured in inches? Pft, what a noob, 1/2 foot diameter is where it's at!

;)

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Rofl hahahaha xD

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using tubing at all is so prehistoric. Now all the hype is direct teleport of water between waterblocks and rad. Zero flow resistance on tubing part and you don't need pump!

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Originally Posted by vhaarr

Cathar's test says otherwise

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Exactly the thread I would have linked to.

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Originally Posted by theseeker

First and foremost, let's begin with the source.:rolleyes:

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Originally Posted by Aaronharmon

The last place I would get water cooling advice is maximum pc

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^-QFT. I spent hours on the phone with those bozos a few years ago (2007?) when they were wanting to write a water cooling feature and water cool their annual 'ultimate gaming PC' build. Totally clueless. My opinion of them also wasn't helped when I sent them a complete custom cooling kit (done specifically to meet their needs) for the water cooling feature they were planning on doing... which they never ended up doing (they just briefly mentioned the kit in an article where they were playing around with a FLIR camera instead). Then they asked me for another complete system like a month or two later for the gaming PC build.

Umm, I don't mean to be cynical but the purpose of a magazine is to make money selling advertisements, not to tell you the truth. The articles that appear in magazines are bad for several reasons: (1) they tell you what you want to hear, because that makes you want to buy the magazine; (2) "product reviews" invariably recommend products made by the biggest advertisers in the magazine; and (3) the publishing industry generally has contempt for the articles themselves, as the industry refers to the articles as the "news hole" in the magazine, because that is the part of the magazine they can't sell to some advertiser. Hence, my point is that Maximum PC is no better or worse than any other magazine, as it is written by the same kind of "magazine journalists" who write articles telling you that can lose 10 pounds in three days by eating only cheeseburgers, or that you can get a six pack of abs by exercising in your chair for 5 minutes a day. So it's not surprising to me to read in the pages of Maximum PC that 1/2" tubing can yield a 10C drop in temps. (Load/ idle, who cares? It's all good.) Now I'm waiting for next month's issue, to find out that switching to 1/2" tubing will help me trim my gut as well, because that is news I can use. :up:

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Originally Posted by eth0s

Umm, I don't mean to be cynical but the purpose of a magazine is to make money selling advertisements, not to tell you the truth. The articles that appear in magazines are bad for several reasons: (1) they tell you what you want to hear, because that makes you want to buy the magazine; (2) "product reviews" invariably recommend products made by the biggest advertisers in the magazine; and (3) the publishing industry generally has contempt for the articles themselves, as the industry refers to the articles as the "news hole" in the magazine, because that is the part of the magazine they can't sell to some advertiser. Hence, my point is that Maximum PC is no better or worse than any other magazine, as it is written by the same kind of "magazine journalists" who write articles telling you that can lose 10 pounds in three days by eating only cheeseburgers, or that you can get a six pack of abs by exercising in your chair for 5 minutes a day. So it's not surprising to me to read in the pages of Maximum PC that 1/2" tubing can yield a 10C drop in temps. (Load/ idle, who cares? It's all good.) Now I'm waiting for next month's issue, to find out that switching to 1/2" tubing will help me trim my gut as well, because that is news I can use. :up:

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Although your reasoning makes sense generally, it doesn't really apply here as the difference in tubing size doesn't benefit any manufacturer or advertiser in their magazine. This is purely ignorance and a lack of proper testing methods.

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Originally Posted by Sideroxylon

Although your reasoning makes sense generally, it doesn't really apply here as the difference in tubing size doesn't benefit any manufacturer or advertiser in their magazine. This is purely ignorance and a lack of proper testing methods.

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Sense of humor much?

Somehow I lost you in making my point by trying to be funny, which is my fault I guess. What I was trying to say is that the magazine is not interested in curing their own ignorance or gaining knowledge, and they certainly don't care about "proper testing methods". All they want to do is sell magazines, because they make money from the ads that appear in the magazine, which they then use to pay themselves huge bonuses, and then they go play golf, have a few drinks and laugh at the nerds who argue about the veracity of the testing methodology used in their magazines.

Let me put it this way: magazine buying people want to read articles that say that 1/2" tubing is better than 3/8" tubing, so that is what gets written in the magazine. The publisher of Maximum PC is giving his readers what they want. Maximum PC doesn't care about "proper testing methods", because they already have their conclusion, and the testing doesn't really matter. Furthermore regardless of the testing methods used or not used, after the story has been written, an editor at the magazine will change the "findings" to give the story the most "sizzle". In this example, I'm sure the editor decided that a 10C delta was a more exciting finding than a .5C delta (which was closer to the actual truth), and so the editor changed the copy. In conclusion then, your allegation of ignorance on the part of the magazine people is completely inapt, for it presupposes a level of conscience that is wholly absent in commercial publishing. In other words, they don't really care about the science or the facts. All they care about is selling magazines, so they write stories that they think people want to read, even if they have to "fudge" the findings.

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Originally Posted by eth0s

Let me put it this way: magazine buying people want to read articles that say that 1/2" tubing is better than 3/8" tubing, so that is what gets written in the magazine.

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Are you still trying to be funny? Why do you think people want to read that? I think the average person reading that mag could care less.

I've read that mag for years and have always found their reviews straight forward and fair. Maybe I'm being a bit naive here but I believe for the most part they try to present the facts and not "what the reader wants to read" or what the manufacturer wants them to print. If that was the case they wouldn't have lasted all these years just printing bull:banana::banana::banana::banana: like that.

I still think it just came down to them getting it wrong this time and not posting those results because the editor thinks that's what we want to read.