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i dont know if the title makes sense but i will try and explain it a little better

i have been looking into watercooling for awhile and i get lots of advice but never take the plunge, however, when looking at the corsair 900D (i am thinking about getting it when its released) i see it can take 2 x 480mm rads, one at the side and one at the top

i was wondering if the fans on the one at the bottom could be intake and the fans on the rad at the top could be exhaust? or do they both have to be the same?

also is 2 x 480mm rads a bit overkill for a single 7970 and 3930k?

i would also have to find somewhere to put the case as it will be too big to fit under my desk, my current HAF X fits okay but the 900D is even bigger

just a quick side question, which others fans would i need if i watercooled my cpu and gpu in the 900D because i assume you still need airflow for the other components...

i seen the 900D has fans at the front but they are covered.. do you take that cover off or does the air go around the sides of the cover?

sorry for all the questions
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Quote:
Originally Posted by Schwuar View Post

i dont know if the title makes sense but i will try and explain it a little better

i have been looking into watercooling for awhile and i get lots of advice but never take the plunge, however, when looking at the corsair 900D (i am thinking about getting it when its released) i see it can take 2 x 480mm rads, one at the side and one at the top

i was wondering if the fans on the one at the bottom could be intake and the fans on the rad at the top could be exhaust? or do they both have to be the same?
I think this would be a good way to go. air in the bottom and out the top is pretty much the standard.
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Originally Posted by Schwuar View Post

also is 2 x 480mm rads a bit overkill for a single 7970 and 3930k?
Maybe, but, it will certainly result in good heat exchange from the water to the air. If you got them, and they fit in the case, I say go for it.
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Originally Posted by Schwuar View Post

just a quick side question, which others fans would i need if i watercooled my cpu and gpu in the 900D because i assume you still need airflow for the other components...
Intake in the front and exhaust in the back is pretty standard. I like to have a PCI exhaust fan fitted below my GPU just to keep air moving over that part of the board and over the Vid card itself. Not a lot of movement needed. It also tends to do a little cooling for the Chipset.
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Originally Posted by Schwuar View Post

i seen the 900D has fans at the front but they are covered.. do you take that cover off or does the air go around the sides of the cover?
Don't know
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Originally Posted by Schwuar View Post

sorry for all the questions
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No problem. You wrote them well with good spelling and grammar. Makes it much easier to read and understand than many these days.
 

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To me, if you have one rad feeding it's exhaust to the other, that equates rad sandwiching. The second rad will loose a lot of cooling power when doing this. I would have both rads pulling in air and your front and back fans exhausting air out of the case.

But you can always experiment and figure out for yourself which configuration performs better for you.

Cheers
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Quote:
Originally Posted by PepeLapiu View Post

To me, if you have one rad feeding it's exhaust to the other, that equates rad sandwiching. The second rad will loose a lot of cooling power when doing this. I would have both rads pulling in air and your front and back fans exhausting air out of the case.

But you can always experiment and figure out for yourself which configuration performs better for you.

Cheers
cheers.gif
Not really. Lots of space between them. Lots of opportunity for other air to be introduced. Lots of opportunity for the air to lose some of its heat. It will pick up some heat from the components, which is the main argument for rads to exhaust in the case instead of out of it., but, it's all a matter of degree (pun intended).
 

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I'm not sure about this, but what about all fans as intakes for a super positive pressure setup? You could either put fan in the rest of the spaces, or air could naturally be pushed out.
I'm not sure about this, just an idea
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Quote:
Originally Posted by Capt Proton View Post

Not really. Lots of space between them. Lots of opportunity for other air to be introduced. Lots of opportunity for the air to lose some of its heat. It will pick up some heat from the components, which is the main argument for rads to exhaust in the case instead of out of it., but, it's all a matter of degree (pun intended).
Are you for real? Do you actually beleive that feeding one rad with the other rad's warm exhaust will not impede performance?

Are you that bent in disagreeing with me as to make such a ridiculous claim?
 

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Quote:
Originally Posted by PepeLapiu View Post

Are you for real? Do you actually beleive that feeding one rad with the other rad's warm exhaust will not impede performance?

Are you that bent in disagreeing with me as to make such a ridiculous claim?
lets face it if he has 2 480's cooling just a single 7970 and 3930k it's not really going to matter

Just for info you have a haf x you con put a thick 360 rad with push pull depending on motherboard, which would be enough to cool them depending on overclocks and voltage needed
 

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Quote:
Originally Posted by Greenback View Post

lets face it if he has 2 480's cooling just a single 7970 and 3930k it's not really going to matter
This - With the amount of RAD you have and what you're cooling, it won't matter how you have your fans configured at all.
But the best way to go with watercooling is always to have your fans moving air from outside the case into the Rad.
 

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Quote:
Originally Posted by fishymamba View Post

I'm not sure about this, but what about all fans as intakes for a super positive pressure setup?
All fans or all rad fans as intake?
If so this is what I was suggesting. This way, neither rads are exhausting into the other one.
 

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I notice you do not mention noise as one of the parameters you are concerned with, you only mention cooling performance.Just one rule (of a small list) Fans can and should be matched to the radiator fin density(a standoff for your fans would also be nice).This matching will help with noise and cooling performance.
 

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Quote:
Originally Posted by PepeLapiu View Post

Are you for real? Do you actually beleive that feeding one rad with the other rad's warm exhaust will not impede performance?

Are you that bent in disagreeing with me as to make such a ridiculous claim?
I am more than for real, I am practical. There are many examples of rads in the bottom pulling air in and a rad in the top exhausting. If it worked as you suggested, then people would not do it. Chances are, the motherboard and other interior components are actually going to be dumping more heat than the rad. Temps on the chipset for example, are likely to be in the 40 - 45 C range. Add that to the many other sources of heat, and there is significant heat produced inside any computer.
 

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Quote:
Originally Posted by PepeLapiu View Post

To me, if you have one rad feeding it's exhaust to the other, that equates rad sandwiching. The second rad will loose a lot of cooling power when doing this. I would have both rads pulling in air and your front and back fans exhausting air out of the case.

But you can always experiment and figure out for yourself which configuration performs better for you.

Cheers
cheers.gif
Quote:
Originally Posted by Capt Proton View Post

Not really. Lots of space between them. Lots of opportunity for other air to be introduced. Lots of opportunity for the air to lose some of its heat. It will pick up some heat from the components, which is the main argument for rads to exhaust in the case instead of out of it., but, it's all a matter of degree (pun intended).
Quote:
Originally Posted by PepeLapiu View Post

Are you for real? Do you actually beleive that feeding one rad with the other rad's warm exhaust will not impede performance?

Are you that bent in disagreeing with me as to make such a ridiculous claim?
Quote:
Originally Posted by Capt Proton View Post

I am more than for real, I am practical. There are many examples of rads in the bottom pulling air in and a rad in the top exhausting. If it worked as you suggested, then people would not do it. Chances are, the motherboard and other interior components are actually going to be dumping more heat than the rad. Temps on the chipset for example, are likely to be in the 40 - 45 C range. Add that to the many other sources of heat, and there is significant heat produced inside any computer.
So far I'm finding in my Switch 810 that having both rads as intake, 240 in bottom and 360 in the roof, isn't making any difference in terms of component temps. Not done testing yet, so far I've only run P95 so only stressed my CPU, 3570K @ 4.6GHz 1.37v, and found load temps to be the same.

Next I'm going to play some crysis 3 so the GPUs will be working 100% each dumping more heat into the loop to see if I get some difference there, I'll also clock them to 1000MHz each at 1.28v. With my previous configuration of 360 rad as exhaust I saw temps as high as 49C on my GPUs so reversed Im hopefully gonna reduce that, by how much who knows, maybe none at all.
 

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People do it because they don't know any better. Its easy enough to see when you put temperature and water sensors everywhere and you see that the air coming out of your front rad is nearly the same temp as the water, is then heated further by components in the case and the air going into the top rad is the same or higher temp than the water it is meant to be cooling. All, or the majority of the work gets done by the front rad.
I saw exactly that with a 240 front rad choking my 360 top rad.

If the components of the motherboard were putting out the same heat energy as a radiator then they would need water blocks themselves. A chipset etc, may well be 45C ... but it is 45C while being passively cooled, CPU's and GPU's are at higher temps while being actively cooled ... if they were not being actively cooled the temps would run away.

Arguing that it doesn't matter when you have two 480's is beside the point, if it doesn't matter then why have the second rad to begin with.
With the exception of a condition where you apply high fan speeds to low radiator loads, radiators are very good at doing what they are designed to do, efficiently flood the air passing through them with as much heat as possible. Feeding one rad with another's exhaust is a waste of radiator space.

While its certainly true that with some builds changing airflow over rads may make little difference to component temps because a surplus existed to begin with ... at the very least it will mean that the same performance can be obtained with lower fan speeds on each rad.
 

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Quote:
Originally Posted by Capt Proton View Post

I am more than for real, I am practical.
Using one rad's warm exhaust to feed a second rad has nothing to do with practicallity or efficiency.
Quote:
There are many examples of rads in the bottom pulling air in and a rad in the top exhausting. If it worked as you suggested, then people would not do it.
Just because some people are doing it does not validate the idea. Plenty of people smoke crack, gamble, and beat women. But just because they are doing it in no way indicates it is the right thing to do.

At one point, when I started WCing, plenty of people, including myself, used aluminium rads and copper blocks. But just because plenty of people were doing it, just because manufacturers were selling it, in no way validated the idea of mixing metals.

Same goes with rad sandwiching. Just because plenty of guys are doing it does not validate the soundness of the idea.
Quote:
Chances are, the motherboard and other interior components are actually going to be dumping more heat than the rad.
That is just plain wrong. The mobo, and HDD's do not produce anywhere near as much heat as the CPU alone, much less the CPU and GPU combined.

But even if your statement above was correct, and it is not, you are suggesting pulling the heat of the first rad, and the heat of all your components into the second rad. That pretty much negates the usefulness of the second rad all together. At this point, I find your priority is to simply disagree with me, no matter what the arguement is.
Quote:
Temps on the chipset for example, are likely to be in the 40 - 45 C range. Add that to the many other sources of heat, and there is significant heat produced inside any computer.
OMG! Maybe you should take off your CPU block and fit it on your chipset?
In case you haven't noticed, mobo blocks are not required because mobo components do not produce enough heat to warrant water cooling. That goes for HDD's and RAM sticks too.

To OP, as Jakusonfire explained, feeding one rad's air to the other is not sound practice. I suggest you have both rads pulling in air or both rads pushing out air. Sure, you have overkill rads here. But I personnally like overkill. Overkill is good!
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But having improper air flow will virtually negate your overkill. What fun is it to.have overkill that will perform similar to regular cooling?

But one sure way to end the debate is to post a Martin quote. So I leave you with the following found here:
Quote:
The trick with rad sizing is the installation where grill restriction, poor case air flow, and recycling of heat can easily cut performance in half or worse.
 

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Quote:
Originally Posted by PepeLapiu View Post

At this point, I find your priority is to simply disagree with me, no matter what the arguement is.
Perhaps so, therefore, no comment.
 

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Quote:
Originally Posted by Matt26LFC View Post

So far I'm finding in my Switch 810 that having both rads as intake, 240 in bottom and 360 in the roof, isn't making any difference in terms of component temps. Not done testing yet, so far I've only run P95 so only stressed my CPU, 3570K @ 4.6GHz 1.37v, and found load temps to be the same.

Next I'm going to play some crysis 3 so the GPUs will be working 100% each dumping more heat into the loop to see if I get some difference there, I'll also clock them to 1000MHz each at 1.28v. With my previous configuration of 360 rad as exhaust I saw temps as high as 49C on my GPUs so reversed Im hopefully gonna reduce that, by how much who knows, maybe none at all.
Just to add, I've since played Crysis 3 at 1000MHz @ 1.28v and my GPU temps where 42C Max, pretty sure I ran the same settings. So I guess reversing the airflow on the top rad has helped, but only when lots of heat is being dumped. Thats not to say theres no difference with lower heatloads in my situation, just noting a Significant change in temps. There may well be a measurable difference in temps at lower heatload, it just depends on how significant 0.5C (example) or less is to you.
 

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Quote:
Originally Posted by Matt26LFC View Post

Just to add, I've since played Crysis 3 at 1000MHz @ 1.28v and my GPU temps where 42C Max, pretty sure I ran the same settings. So I guess reversing the airflow on the top rad has helped, but only when lots of heat is being dumped. Thats not to say theres no difference with lower heatloads in my situation, just noting a Significant change in temps. There may well be a measurable difference in temps at lower heatload, it just depends on how significant 0.5C (example) or less is to you.
When doing this kind of test, you should log ambient temps too. Even a minor 3-4c fluctuation in your ambient temps will produce a fairly big difference.

Also, idle core temps are not very relevent. It's not uncommon to have a WC rig with higher idle temps than when air cooling. It's under load that WCing shines above air cooling.
 

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would not having case fans as intake bringing in air negate some of the warm air from the first rad before it reaches the top rad, e.g. looking at the 900d has 3 fans at the front if set to intake they would cancel out most of the effect from the bottom rad
 

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Quote:
Originally Posted by PepeLapiu View Post

When doing this kind of test, you should log ambient temps too. Even a minor 3-4c fluctuation in your ambient temps will produce a fairly big difference.

Also, idle core temps are not very relevent. It's not uncommon to have a WC rig with higher idle temps than when air cooling. It's under load that WCing shines above air cooling.
Ambient largely stays the same, around 19C in my 3rd bedroom, the weather hasn't changed much in the last day
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None of my temps that I've thrown up are Idle, there all load.
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Originally Posted by Greenback View Post

would not having case fans as intake bringing in air negate some of the warm air from the first rad before it reaches the top rad, e.g. looking at the 900d has 3 fans at the front if set to intake they would cancel out most of the effect from the bottom rad
I would say that it would, its not like the rads are sandwiched together. I don't know by how much the air introduced to the case would help negate the warmer air coming from the rad though. I guess the only way of really knowing is by putting temp sensors all over the place.

I do believe Martin is going to be testing this at some point with the Switch 810 case he has, so I guess well all get some very detailed results with regards to all of this sometime in the (hopefully) near future
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I know martin mentions when he did the review on the H220 that he put it on the bottom so he could expand to a 360 on the top, So me thinking how martin works he will probably do it then.

If I could be bothered to drain my loop (I should I know after 14 months) I could test the air in- air out but having 480 worth of rad for just a 2500k and 6870 I don't know if it would even show enough to register.
 
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