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140mm for 2x465?
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Technically, yes, but it kind of defies the point of water cooling in the first place. It will be noisy and hot.
I'll walk through it:
Let's take a 1x140mm rad, in this case a Koolance HX-CU1401V, which has a very high 30 fins-per-inch, meaning you need good strong fans to have it perform well.
Koolance has a graph showing watts dissipated vs. flow rate; you can see that using this fan running at 1700rpm/91CFM and 36dB, the rad dissipates 400-450w at a 25C delta T. Now, 25C is pretty high - significantly higher than most WC'ers run their loops at. Nevertheless, it should still be within the thermal operating envelope of the hardware.
Okay, so now the question is how much heat do we need to dissipate? Looks like a pair of GTX 465s in SLI consume between 315-390w, while a GTS 250 adds another 80w. Bear in mind the lower number for the 465s represents a more typical gaming load, while the higher number is full power stress testing. So, during gaming we could expect all three cards to put out about 400w of heat, coincidentally about what our rad can handle at a 20-25c delta. Of course, 100% of the heat doesn't go into the loop; some of it will dissipate off the back of the cards, for example. But the majority of it will. The overall efficiency will also depend where your rad is located and if it's acting as an intake or exhaust.
So yes, a single 140mm rad can handle all that. It won't be ideal though, in terms of noise and temps, and a different 140mm rad may not perform as well. You can improve the rad's performance by using shrouds, higher speed fans, and/or two fans for push/pull operation.
Hope that helps.
I'll walk through it:
Let's take a 1x140mm rad, in this case a Koolance HX-CU1401V, which has a very high 30 fins-per-inch, meaning you need good strong fans to have it perform well.
Koolance has a graph showing watts dissipated vs. flow rate; you can see that using this fan running at 1700rpm/91CFM and 36dB, the rad dissipates 400-450w at a 25C delta T. Now, 25C is pretty high - significantly higher than most WC'ers run their loops at. Nevertheless, it should still be within the thermal operating envelope of the hardware.
Okay, so now the question is how much heat do we need to dissipate? Looks like a pair of GTX 465s in SLI consume between 315-390w, while a GTS 250 adds another 80w. Bear in mind the lower number for the 465s represents a more typical gaming load, while the higher number is full power stress testing. So, during gaming we could expect all three cards to put out about 400w of heat, coincidentally about what our rad can handle at a 20-25c delta. Of course, 100% of the heat doesn't go into the loop; some of it will dissipate off the back of the cards, for example. But the majority of it will. The overall efficiency will also depend where your rad is located and if it's acting as an intake or exhaust.
So yes, a single 140mm rad can handle all that. It won't be ideal though, in terms of noise and temps, and a different 140mm rad may not perform as well. You can improve the rad's performance by using shrouds, higher speed fans, and/or two fans for push/pull operation.
Hope that helps.
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- Mar 18, 2010
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- 14,448
I'll let you know how a 3x140 radiator performs with 3 1500 RPM fans (Aerocool Silver Lightning) and 2 GTX 470's and a Phenom II 1090T at 3.8 ghz. But just for reference, it kept this system with 2 GTX 275's and a Phenom II 1090T barely below 60 C on the GPU's. I would hate to see it with a single 140. This is uisng a GTS 420.
Okay sounds like a start and my mind was somewhere else because I meant a gts 450 not 250. Sounds like a 140 is on the edge,I may be able to add an additional 120 and both would be exhausting out of the case. This is the case http://www.newegg.com/Product/Product.aspx?Item=N82E16811119228 The case has a 140 front intake a 140 top exhaust as well as a 120 rear exhaust,in addition to two 120/140 on the side panel. I already have the 120 and 140 rad so that would be cheaper. How does fluid volume factor into this? Should I use a small reservoir or large one?
- Joined
- Mar 18, 2010
- Messages
- 14,448
Small vs large reservoir doesn't matter, just use whatever suits your fancy.
Use both radiators, you might be able to pull it off with decent temps. Otherwise, I would mod the top for a 2x140 radiator, and use that with the 120.
Use both radiators, you might be able to pull it off with decent temps. Otherwise, I would mod the top for a 2x140 radiator, and use that with the 120.