RBX, How good is it?

Checkout Danger Den's site, there is a new review linked there.

Hrm, we definitely need a better translation. I can barely make out the context using InterTran. Couldn't grasp their testing method either.

If I'm not mistaken, the RBX by their chart was 2C better than the Maze 4... I think that says it all as the Maze 4 is a horrible performer.

nikhsub1 said:

If I'm not mistaken, the RBX by their chart was 2C better than the Maze 4... I think that says it all as the Maze 4 is a horrible performer.

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only 2C better than Maze4??? I expected alot more

More interesting is how the WW is 1c better than the Maze4 Anyone seen the insides of that Magnum block?

Soja said:

More interesting is how the WW is 1c better than the Maze4 Anyone seen the insides of that Magnum block?

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wtf?????

ILikeMy240sx said:

only 2C better than Maze4??? I expected alot more

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I personally regard most tests done by the Germans as invalid for the "English" speaking markets. This is not so much because they suck at testing, but because of the test conditions.

The test-bed in question is just a single mount of a water-block. There is no accounting for mounting variations.

The major issue here though is the flow rate and test setup used by many of these testers. The WCP testbed consist of an Eheim 1046 (5LPM, 1.2m pressure head rated pump). An Eheim 1046 is lucky to push 4LPM in wide-open mode with its fittings attached. The pump is then pushing through about 2m of 8mm tubing, and attached to a radiator that consists of 24 elbows of continuous copper 8mm tubing (just by eyeballing the pictures of the radiator). Before a waterblock is even attached, we're probably looking at well below the 2LPM mark in terms of actual flow rates.

Now the issue with performance for lower flow rates is that it is beneficial to have a thicker base-plate than a thin base-plate because the copper conduction "costs less" than the reduction in convectional cooling benefit through having the lower flow rates, and so it's better to have more copper to allow the heat to spread to a larger area to be cooled. As the flow rates are increased, the copper starts to get in the way and hinder the potential cooling performance.

This is perhaps best illustrated by Bill Adam's flow vs C/W graphs:



Notice how at below 2LPM that the MCW5002 and the White Water are pretty close? This is the thin base of the White Water coming into effect here dragging its performance back. The White Water was designed to operate in >4LPM environments and its base-plate was designed around that to achieve better performance as one pushes past the 4LPM mark. Now an Eheim 1048 attached to a heater-core and a White Water will achieve ~5LPM, so we're not talking about requiring large pumps here - just a regular smallish pump that most people would use.

Notice also how from somewhat humble beginnings that the White Water stretches its lead dramatically and it still continuing to show good improvement towards the end of the curve while the other blocks that started near it are almost flat-lining. This the the difference in base-plate thicknesses showing through here.

The RBX has a thicker base-plate than the White Water. The Cascade is even thinner than the White Water but you can still see the admirable showing that it puts in.

As one starts to boost the flow rates into "normal" levels, rather than the artificially low ~1.5LPM flow rates that the WCP test-bed uses, the performance picture will change quite dramatically.

As a side note, the Cascade tested there was a first rev block that had been modified by the buyer prior to sending it in for review, without my knowledge. A number of streamlining improvements have been made to the block since then, and I certainly would have appreciated an unmodified block being reviewed.

[Edit - I should add that I'm referring to the review of the RBX, Cascade and WW over here: http://www.watercoolplanet.de/index.php?open=4&show=1

thank you so much Cathar for that wonderful englihtment... I knew I shouldve thought about flow rate bias... I remember seeing this other time when cascade was second... They completely crippled the flowrate of cascade.

Now I know... thanx

Subquestion...

You mentioned that when low flowrate is given, thicker copper is beneficial... but what is the factor(s) that separates the block at low flowrate besides the thickness of the base?

In the graphs I see 3 groups at low flow rate. The top group being 5002 and WW

how thick is the base of the WW? i thought one of the main features of the RBX was that it was so thin in the center. on the wesite it says at the base of the "heat voids" it is .025".

ILikeMy240sx said:

You mentioned that when low flowrate is given, thicker copper is beneficial... but what is the factor(s) that separates the block at low flowrate besides the thickness of the base?

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I guess you can just lump it under "waterblock design efficiency". Each block is different in how it utilises the water flow to transfer the heat of the CPU into the water. This is highly dependent upon the block's design. The ones that you see at the upper side of the graph will generally have poor design characteristics for getting the heat into the water, such as largish expanses of copper without any turbulence or added surface area where it's most needed to facilitate better transfer of heat into the water.

When I think of waterblock design, I tend to think of it like this:

"How can I ensure that as much as possible of all the water-molecules that flow through the block can come into contact with the copper as close as possible to the CPU"

I guess that about sums up my waterblock design philosphy in a single sentence, and if you look at some designs where the water just rushes about but a large majority of it never gets close to where the heat is, then that will go a long way to helping to understand why some blocks perform worse than others.

zip22 said:

how thick is the base of the WW? i thought one of the main features of the RBX was that it was so thin in the center. on the wesite it says at the base of the "heat voids" it is .025".

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The documentation on the RBX says that it has two base-plate thicknesses really, 0.025" and 0.05". On average you're probably looking at close to 1mm (0.04") for the RBX. The White Water is pretty close in thickness to the thinner sections of the RBX.

Really would like to see JoeC (Overclockers) do a comparison of the RBX and the White Water as his test-bed is closest to what people are doing today.

Cathar said:

"How can I ensure that as much as possible of all the water-molecules that flow through the block can come into contact with the copper as close as possible to the CPU"

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Sweet idea. I don't think anyone can come up with a better design model than that. That's why he's Cathar.

If this is the case, then the RBX probably can't be as good as the WW or Cascade. The area covering the cpu contact point doesn't seem to create that much turbulence. Its slits are surprisingly at the two ends, far from the center. This is just my two cents.

Cathar said:

I guess you can just lump it under "waterblock design efficiency". Each block is different in how it utilises the water flow to transfer the heat of the CPU into the water. This is highly dependent upon the block's design. The ones that you see at the upper side of the graph will generally have poor design characteristics for getting the heat into the water, such as largish expanses of copper without any turbulence or added surface area where it's most needed to facilitate better transfer of heat into the water.

When I think of waterblock design, I tend to think of it like this:

"How can I ensure that as much as possible of all the water-molecules that flow through the block can come into contact with the copper as close as possible to the CPU"

I guess that about sums up my waterblock design philosphy in a single sentence, and if you look at some designs where the water just rushes about but a large majority of it never gets close to where the heat is, then that will go a long way to helping to understand why some blocks perform worse than others.

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^^ That's worth a sticky (no kiddin)

Sneakytermite said:

If this is the case, then the RBX probably can't be as good as the WW or Cascade. The area covering the cpu contact point doesn't seem to create that much turbulence. Its slits are surprisingly at the two ends, far from the center. This is just my two cents.

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Hmmm, from an eyeball perspective, the RBX and the White Water would be fairly close in performance, but as always with caveats. The White Water has a higher fin density, but the RBX has added turbulence features. The White Water has a thinner base-plate on average that enjoys middling-higher flow rates, but the RBX has a slightly thicker base-plate (on average) which would favor marginally lower flow rates.

The two designs have their merits as to their respective approaches. As to which would perform better, I feel that is best left to an independent properly calibrated test-bed to decide, unlike many of the reviews that are about which are showing margins of error in the 3-4C range making it impossible to distinguish anything.

JoeC offers perhaps the best test-bed for that, but I'd also like to see him test at flow rates higher than the ~3.5LPM that he does test at, since that's still a little low IMO as even an Eheim 1048 with a decent heater-core will see flow rates quite a deal higher. Ideally JoeC should be testing with at least 4 flow rate points to give an idea of what people can expect across a range of pumping scenarios.

Cathar said:

The White Water has a higher fin density, but the RBX has added turbulence features.

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It's not at all clear to me that the "turbulence features" will be beneficial. They look like places for water to get somewhat 'stuck' to me.

I'm definitely looking forward to seeing some quality testing results.

For me RBX base looks like it shouldn't make water stuck, maybe wit h these wider spreaders.

Adding good Cascade-style sprayers should be benecicial, tho...

The center of the RBX doesn't seem to be able to create that much turbulence since its holes are too small and may be neglectible.

what? could you elaborate on that sneakytermite

i would think that any irregularities in the surface would cause more area for the water to hit, even the slightly rough texture of the RBX.

Actually, i ordered the RBX also..
like last wednesday.
I'm waiting for it to setup my watercooling system
I wanna know the result also.