Dual Loop versus Single, the facts

[gabe]

Dare I post among these giants of the group....
Sure.

Interesting read. Nice work...

However, Trekkies, don't talk about the force, that's Star Wars...

But THANK YOU for not calling us Trekkers. I wish they had never started that.

I have edited my post to "Jedi Masters" instead of "Trekkies". Sorry for the historical confusion .

That's a fantastic post. I wonder what the power draw is at load?
@Gabe: How much do you feel that temperatures would suffer under the following conditions:
Dual MCP350's instead of dual 355s?
Or using a single MCP 350.
I would imagine that it would be quite easy for one of your many clients to add a dual radiator to their existing loop with your products.

If you refer to Part I of this article, you will observe that flow rate has a nominal impact on the water-blocks that we are using in this setup. See below regarding using (1) pump.

Great guide! I still wonder, though... is it better to have two pumps under one top at one point in a loop, or two pumps at different points in a loop?

Also, there's probably a really good guide out there, but I can't seem to find one: Anyone know how much of a performance gain you get with two pumps under one top instead of just one pump?

As long as you have two pumps in the same loop, irrespective of their position in the loop, you benefit from the redundancy factor and this is a huge plus for a high end system.

(1) pump instead of (2), see below..

awesome review! looks like single loops wins. now if you were to add one more twist, which one would win in this scenario: a single combined loop with only one pump, or a two separate loops with a pump in each loop? basically, the only thing that's changed is that the combined loop with one less pump. taking one pump away would mean less pressure/flow, but that also means that the heat from that pump is not dumped into the loop. so now, any ideas which one would win?

1. The heat from the pump that goes into the system is less than 3W, compared to ~550W generated by the CPU&GPU devices (in SLI config). It's less than 1% of the overall load, thus negligible.
2. Part I of this article demonstrated the limited effect of flow rate variations on this generation of waterblocks, so the performance loss would also be nominal.
3. In general use and by simple virtue of the asymetric load (load ratios of devices vs. heat exchangers), the serial configuration would still pull comfortably ahead.
4. In extreme use, there is no question that dual loops would be ahead but the limited scope of this usage model does not infirm the conclusions of this article.
5. Using (1) pump instead of two certainly reflects the majority in terms of usage model; from a performance and economic standpoints, this seems like the sweet spot; on the other hand, one could argue that when people invest so much money in hardware, reliability alone could easily justify the investment for a second pump. Up until now, dual loop setups have been more complex and/or often difficult to implement because of space constraints; however the introduction of the MCR-Drive series of radiators with integrated pump considerably simplifies the integration task, particularly in light of the upcoming new generation of Radiators that can now operate horizontally (hint hint hint ).

Good! Another very informative post, big thumbs up.

I never really understood the multiloop train of thought other than decreasing restriction. With restriction in mind, a single loop with just one pump like suggested is what i would really like to see as that is what i'm using atm.

How important is flow for a sinlgle loop, especially with 2 videocards?

Keep up the great stuff Gabe!

See Part I, but keep in mind that the effect of flow is highly dependant on the type of water-block that one uses. Unquestionably, F/C blocks with simple channels for example will be much more sensitive to flow rate than the micro-pin technology that we employ; opposite to this argument however is the fact that current graphic dies have a much lower internal thermal resistance than CPU's due to their huge footprint, which results in lower temps than CPU's. Thus the loss of a few degress may not be as critical as it would be with CPU devices.

Nice testing indeed. . .but, all these results are with 355's. I'm curious what would happen to the results if 655's were used instead. There are those out there that flat out refuse to use DDC's for whatever silly reasons they believe in and this testing really doesn't help them.

The absolute temperature values would differ, but the trends wouldn't.

Thanks for doing this, as always it's great stuff!

Is there any chance you could put this and the other white paper into a PDF for easy printing? This is the kind of stuff I like to have a hard copy of and make notes on.

Done! http://www.swiftnets.com/Technical/T...l_Articles.asp