Loop Order, Passive WCing

[Breex243]

Now, I generally know that loop order doesn't matter much, but here's two variants of my WC loop I have planned:

Plan A:
'77 Bonnie-->res-->CPU-->NB-->SB-->9600GT-->9600GT-->'77 Bonnie-->Danger Den 3*120mm rad-->pump--Return to 1st Bonnie.

Plan B:
'77 Bonnie-->res-->CPU-->NB-->SB-->'77 Bonnie-->(9600GT*2)-->3*120mm Rad-->Pump

Right now, I can only have 1 loop, although I was thinking of having the 9600s cooled by the 360 rad, which is a bit of an overkill.

You may be wondering why I've got so many radiators...well the whole thing will be cooled passively (although I can add two 120mm fans to the second Bonnie, so I've estimated that I can put off 100W on each Bonnie, and 100W for the 3*120 (tiny fins, not so great for passive use). Currently running an OCed e6750, planning on jumping to an e8400 if someone's willing to sell for under $110, shipped to NY.

Giving my CPU headroom to hit 4.2 with an e8400, I've got 133W coming from it. The NB/SB gets INCREDIBLY hot on my 780i, so I'm giving those another 40W. The eXtreme PSU calculator gives me 75W for both my 9600gts. Flow rate will only be about 100Gph.

Question is: Is plan A safe? Having 200W of heat rushed past my GPUs? I won't be overclocking my GPUs much, but I'd hate to have to do a re-build if my GPU temps are too toasty. If this was a normal system, then I wouldn't really worry, but the fact that my system will be passive (and thus water will be naturally warmer), is starting to raise some worries.

Also, any recommendations for V splitters anywhere?

 

[Erasmus354]

Your estimates might be high for passive cooling. I would guess 50-75W maximum with a 10C delta between coolant and air. (single 120 can go down to 75W with a fan on low rpm's)

I wouldn't concern yourself with the order of components. I would just look at the big picture, total cooling and total heat dissipation capacity. As long as your pump is good the coolant will be moving too fast to heat up much through each component.

 

[Breex243]

Thanks a lot for the advice, Erasmus!

Your estimates might be high for passive cooling. I would guess 50-75W maximum with a 10C delta between coolant and air. (single 120 can go down to 75W with a fan on low rpm's).

Yeah, I'm going to initially install a pair of enlobals on the inside of my case and see what my temps are. If it's still too hot, I'll replace them with the stock Gigabyte fans. If I find that I don't need them, then I can keep them unplugged (although they're dead silent). I used Martin's LiquidLab's charts and 75W seems to be a conservative guess. I can keep my room at about 60C in the summer though, and I don't mind a chilly room in the winter either.

I wouldn't concern yourself with the order of components. I would just look at the big picture, total cooling and total heat dissipation capacity. As long as your pump is good the coolant will be moving too fast to heat up much through each component.

Yeah, I've read that the delta Ts of most water in/out of hot components is only like 2-3C. However, I don't think that many people will be having the amount of pressure I will be having (I'll be needing probably a full 12-13ft of head), so 100-120GPM was my estimate. This is about 50% slower than most loops I've seen, so I'm not sure if the heat buildup will be that bad after a series of hot components, where bad = difference of 6-7C between CPU water in and GPU water in.

 

[Erasmus354]

2-3 C per component is an INSANE temperature increase. Even if your flow was down to 2lpm (very slow) and lets assume your CPU is the hottest component overclocked at 200W, your temperature increase would be 1.4C for that 200W. For your entire loop you are looking at probably 3-4C increase from START to FINISH with slow flow, most loops are within 2C.

 

[Breex243]

2-3 C per component is an INSANE temperature increase. Even if your flow was down to 2lpm (very slow) and lets assume your CPU is the hottest component overclocked at 200W, your temperature increase would be 1.4C for that 200W. For your entire loop you are looking at probably 3-4C increase from START to FINISH with slow flow, most loops are within 2C.

Thx for the info! Good stuff.