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Does more Radiators mean better cooling?

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Kuya

Registered
Joined
Jan 8, 2007
*This is my first post*

My plans for my new water cooling setup has the option of including 3 different radiators, one on top of the case, one in front, and one in the back. Does having 3 radiators instead of 1 mean better cooling for my CPU/GPU? or is 3 just overkill?

Also, with multiple radiators, what is an effective loop setup?
1. Reservoir -> Pump -> CPU -> Radiator -> GPU -> Radiator -> Chipset -> Radiator -> Reservoir?
2. Reservoir -> Pump -> CPU -> GPU -> Chipset -> 3 Radiators (Parallel Setup) -> Reservoir?

Thanks in advance for any help~!

-Kuya
 
Three is overkill.
Two is overkill.

You are much better off just increasing the size of your primary heatexchanger to cope with the heatload rather than adding multiple rads.
 
Clocker2, that's not a good assumption, it could be underkill if he's using 3 80mm rads. :beer:

For the order as long as you have the reservior feeding the pump, put the rest of the components in a way that is the easiest to route the tubing. I'm assuming you're using 3 120mm radiators, in that case you should not skimp on your water pump. 3 120mm radiators in series is probably not overkill, if you have a high end system which puts out a lot of heat.

After about 3x120mm fans in radiator surface area you will get diminishing returns from adding more rads, depending on the system.

Oh yea... Welcome to OCF!
 
Thanks for the fast replies guys!

I am one for over kill when it comes to cooling, I was going to have a total of 4 water blocks in my system: 1 for the CPU, 2 for the dual 7900 GTX's, and one for the chipset. All overclocked of coarse - this setup would generate a considerable amount of heat. The top mounted radiator is a 3x120mm fan Black Ice Extreme, the front is a 1x120mm fan Thermochill PA160, and the back is a 2x120mm fan Black Ice Extreme. If I used all three radiators, although there would be dimenishing returns, would there still be a noticeable change in the temps with each additional radiator?

Oh also, I was planning on using a modded MCP 350 which has a considerable amount of head to hopefully accomodate this multi-radiator/water block system.

-Kuya
 
Maviryk said:
Clocker2, that's not a good assumption, it could be underkill if he's using 3 80mm rads. :beer:
I didn't make any "assumptions", just a recommendation.
If in fact, he is using three 80mm rads, then "increasing the size of your primary heatexchanger" would be a good move.

If the cost/complexity ratio makes sense to you then entirely seperate loops would work- each rad being sized for the heatload- but it is a rare system that would overwhelm a quality single 120.3 radiator.
 
Concentrate your efforts on getting a REALLY powerful pump instead of adding more radiators to your loop. One 3x120mm is plenty, but if you must have more add just the 2x120mm in the back. The single 1x120 in the front isn't going to add any kind of benefit.

I would recommend considering one of these
http://www.performance-pcs.com/catalog/index.php?main_page=product_info&cPath=201&products_id=20552
and two of these
http://www.performance-pcs.com/catalog/index.php?main_page=product_info&cPath=201&products_id=20655
 
@clocker2, What do you mean by "overwhelm" a quality single 120.3 radiator? As in would cool better or would be not worth while?

Also, you got me curious, how would one make 3 seperate loops with one pump? I'm no expert when it comes to hydraulics, would it go like this:

..........GPU -> Radiator -->---->----->----\
......../.....................................................\
Pump -> CPU -> Chipset -> Radiator -> Reservoir -> Pump
........\..................................................../
..........GPU2 -> Radiator --->--->--->----/

Edit: Sorry about the "..." I couldn't figure out how to keep the "/" marks in place. >.<
 
You make separate loops by having separate loops with a pump for each one. He wasn't referring to a parallel arrangement. Put both GPUs and maybe the chipset on a seperate loop with the 3x120mm radiator with a moderate level pump like a Via Aqua 1800. Then put the CPU on it's own loop with the 2x120mm and a powerful pump like a Laing DDC with the Petra's Top.
http://www.petrastechshop.com/laddcwpeddto.html
 
Captain Slug said:
Concentrate your efforts on getting a REALLY powerful pump instead of adding more radiators to your loop. One 3x120mm is plenty, but if you must have more add just the 2x120mm in the back. The single 1x120 in the front isn't going to add any kind of benefit.

I would recommend considering one of these
http://www.performance-pcs.com/catalog/index.php?main_page=product_info&cPath=201&products_id=20552
and two of these
http://www.performance-pcs.com/catalog/index.php?main_page=product_info&cPath=201&products_id=20655

Very interesting, will the DDC Dual Pump attachment work with two modded MCP 350's, also will it really make a difference? A single modded MCP 350 already almost doubles the flow rate. Moreover, I hear rumors that increasing the flow rate won't make a difference at all in the temps, people often refer back to the race car track analogy:

Quote from http://xoxide.com/water-cooling.html:

"There is a debate within the water cooling community about what size tubing is superior. A 1/2" inner diameter system will offer higher possible flow rates than a 3/8" system, but higher flow isn’t necessarily desirable. As long as water is moving in the system, it will spend the same amount of time in the radiator regardless of how fast it’s moving. (If this sounds weird, imagine a car going around a racetrack. The car will spend the same amount of time in a given section of track regardless of how fast the car is moving, because if the car moves more quickly, it will spend less time traveling through the section per lap but make more laps.)"

Will using dual pumps and increasing the flow rate even help? Thanks again guys <3 these forums already~!

-Kuya
 
Captain Slug said:
You make three separate loops by having three separate loops with a pump for each one. He wasn't referring to a parallel arrangement.

Ah, ok thanks Captain Slug. =)

-Kuya
 
Using the double top is not about flow rate, it's about head rate. Which you will seriously need to overcome all the restriction were you to use 3 radiators in series along with 4 waterblocks. And yes that dual top will work with MCP350s or MCP355s. The latter being preferable due to its improved performance.

Oh and welcome to the Forums. :welcome:
 
Ah, *sorry, I'm still newbie* It doesn't look like the double top can be used with the MCP 350 mod, but if I do end up going for 3xRadiators - what attachments do I need for the G 1/4" slots on the dual top to connect it to 3/8" ID tubing?

*Sorry, for more newbie questions, just don't want to have it finally arrive, flush out the system, and it turns out I can't hook it up*

Thanks again,

-Kuya

Edit: Will a single MCP 350 have enough head for 4 waterblocks and a single 120.3 radiator?
 
Well first of all I don't recommend using 3/8" tubing. If you're aiming for overkill then 3/8" ID isn't going to cut the mustard. Use 1/2" ID 3/4" OD tubing, or do some research on 7/16" ID 5/8" OD tubing which is growing in popularity due to it's unique mix of function and performance.

The best 1/2" ID G1/4 fittings you can get are these: http://www.petrastechshop.com/ekhifig1th1o.html
Use Masterkleer 1/2" ID 3/4" OD tubing (go to http://www.mcmaster.com and search for 5233K68)
And to clamp them onto all of your barbs get constant spring-tension clamps which you can apply using vice-grip pliers (mcmaster part# 5324K16)

Or use 7/16" ID 5/8" OD Masterkleer which doesn't require clamps
http://www.petrastechshop.com/7id5odmagepu.html
Simply dip it in really hot water before pushing it onto your barbs.
 
Thanks Slug, very very helpful. Still wondering though, the 1/2" tubing would be to increase flow rate right? But will increasing flow rate really help temps? I can't seem to find evidence either way.

Edit: Looking again at the test results for a modified MCP 350 with 3/8" ID tubing, the flow rate is nearly the same as a MCP 655 with 1/2" ID tubing, the MCP 655 just has less head - seem a modded 350 with smaller tubing has the advantage imho.

-Kuya
 
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The 1/2" tubing will reduce restriction, which will increase flow rates. And yes reducing restriction where it doesn't affect thermal transfer will improve flow rates and therefore thermal performance. There is an upper limit at which increasing the flow rate will not affect your temperatures positively, but you're designing a loop with alot of restriction that needs to be removed, and overcome by a pump with a very high headrate. The more tubing and devices you put in a loop, the higher the headrate you need to overcome it in order to make the most out of the loop as a whole.

Take that modded MCP 350 and give it 1/2" barbs and you'll have a higher output head rate and improved flow rates. But neither of those would even compare to a Laing DDC-2\MCP355 with a Petra's top or a dual DDC-2.

Flow rate is simply the amount of water the pump can output in a given amount of time if pumping against no restriction.
Head rate is a measure of how far the pump can shoot the water against the force of gravity, this denotes the output pressure of the pump. A higher head rate means that the flow rate of the pump drops off much slower as restriction is added.
You can't compare tubing sizes based on the performance of the pumps using certain sizes. The reality is that 3/8" ID tubing is going to involve far more restriction than 1/2" ID tubing, and restriction is something you should avoid wherever possible in order to maintain an optimal flow rate.
 
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Kuya said:
Very interesting, will the DDC Dual Pump attachment work with two modded MCP 350's, also will it really make a difference? A single modded MCP 350 already almost doubles the flow rate. Moreover, I hear rumors that increasing the flow rate won't make a difference at all in the temps, people often refer back to the race car track analogy:

Quote from http://xoxide.com/water-cooling.html:

Will using dual pumps and increasing the flow rate even help?
The race track analogy, along with some of the information on that page, is flawed.

Tubing is easy...bigger is always better, but for most systems 3/8" is big enough. "Big enough" means that you won't see an improvement by going to 1/2" tubing. If you have a CPU block, NB block, and two GPU blocks then I would say stick with 1/2". Otherwise, 3/8” is good enough.

As for the racetrack analogy, it tries to demonstrate that water spends the same amount of time in any given component at slow or fast rates. Although that’s true, it’s meaningless. If it really did have meaning, then there would be no reason to use anything but the cheapest, weakest pump we could find. Obviously that’s not the case.

The time water spends in the block or rad is very important on a per lap basis. This is what the racetrack analogy misses. Flow rate determines how hot water gets when it flows through a waterblock. The cooler the water remains, the cooler the block will be. Because of this fact, it is the temperature fluctuations within one cycle that are all-important in determining how your loop behaves...not how much time water spends in a rad per hour. Faster flow = smaller fluctuations = cooler processor.

As for flow rate, more flow is better until you reach about 1 gallon per minute. At that point, more flow is technically better but the improvements are so small you can't measure them. Further, since more flow requires a more powerful pump and the work of pumping turns into heat, excess heat may negate any benefit from increased flow. For most simple systems (one CPU block and maybe a GPU block) the Laing DDC-1 is good enough (MCP350.) For a system with a Storm and two GPU blocks, a Laing DDC-2 is good enough (MCP355.) In my opinion those aftermarket tops are a waste of money.

But then again...it's your money...buy whatever makes you happy! :)
 
Critics here at oc forums were saying:

"two rads will inhibit the flow and increase your temps"

"you should never put two rads in the same loop because its too restricive" "

"you wont get the temps lower anyway"

Solution:

Get a second pump.... critics have been silenced.... its really not that hard....
 
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