Custom PC Build H115 Cooler fan/Motherboard connection

Newbie here. First time attempting to build a PC. Beginning to think I’m in way over my head. I’m comfortable inside a PC case. Replaced hard drives, video cards, memory, network cards etc. Just never built a PC from scratch before. Thought I’d give it a try.

 

Components:

Corsair Crystal 570 Case

Gigabyte X299 Designaire MB

Intel i7-7820X CPU

Samsung 960 EVO M.2 SSD

Samsung 969 EVO SSD

Corsair H115i Pro Cooler

EVGA G3 750W power supply

32GB DDR4-3200 Memory

 

Case comes with 3 fans on the front but I bought the Corsair 115i to keep the CPU cool. One of the issues is that with the radiator and fans mounted to the top of the case (the only available place to put it) it blocks access to some of the power connections at the top of the motherboard. Hopefully I either won’t need access to those or I can hook up the ones I do need and then mount the H115i back in place.

 

My main issue is that the MB cooling fan header (as it’s called in the manual) is 4 pin whereas the power cable coming out of the Corsair H115i is 3 pin. In that case, can I plug the 3 pin connector into a 4 pin receptacle on the MB and if so, which 3? IOW, which one do I omit?

My main issue is that the MB cooling fan header (as it’s called in the manual) is 4 pin whereas the power cable coming out of the Corsair H115i is 3 pin. In that case, can I plug the 3 pin connector into a 4 pin receptacle on the MB and if so, which 3? IOW, which one do I omit?

 

Yes, it can be plugged in to a 4-pin header. You should plug it into CPU_FAN. This header is only there to provide a tach signal to the motherboard so you don't have a CPU_FAN warning on boot.

No, you almost inevitably run into plug/VRM/RAM collision issues up top. This almost never works on the 570.

 

1) send it back and get the H150i for the front intake mount.

 

2) strap the 280mm behind the existing front 120x3 and then the 2x140 behind the radiator. Shown in this thread.

 

There are quite a few takes on this over the last two years. A quick Corsair 570 & h115 search will give you more than you want to read and this is a common obstacle.

I was able to mount the H115i to the top without difficulty but it was only after mounting it and reviewing the motherboard manual for hookups that I realized that the radiator/fan combo was blocking some of the power connections on the motherboard.

 

The power connections blocked:

Sys fan2 (don’t know if I need this or not)

ATX 16 pin (don’t think I need as motherboard CPU connector looks like it’s 24 pin and that connection isn’t blocked)

LED C2 (don’t know if I need this either)

CPU OPT

CPU FAN

 

So if I need to use the CPU FAN connection, I can get to it by dismounting the Radiator/fan assembly and I can probably remount it. If that’s the only connection I need to make, I’m probably ok.

 

But again, I’m told that the 3 pin connector can go onto the 4 pin connection on the motherboard but does it matter which 3?

Can’t return as I bought it too long ago. A little frustrating though that both products are Corsair and they aren’t compatible with each other.

ATX 16 pin (don’t think I need as motherboard CPU connector looks like it’s 24 pin and that connection isn’t blocked)

No, you need this to power the CPU. Motherboard manufacturers are not in the habit of putting power connectors on the board that you don't need.

 

So if I need to use the CPU FAN connection, I can get to it by dismounting the Radiator/fan assembly and I can probably remount it. If that’s the only connection I need to make, I’m probably ok.

 

But again, I’m told that the 3 pin connector can go onto the 4 pin connection on the motherboard but does it matter which 3?

 

It'll only go on one way; there's a guide. So ... yeah, it does matter which three but it'll be really difficult to put it on incorrectly.

If all the motherboard connections need to have something plugged into them, then I’m way short connectors. Just as the power supply has more connection cables than components that need power, I assumed that there were extra connections on the motherboard for additional hardware and that some of them wouldn’t be used.

 

On the subject of cooling fans, are there any that don’t have lighting? This isn’t going to be used as a gaming PC and I don’t care about lighting up the inside of the case.

The power supply didn’t seem to come with a 16 pin plug but it did come with a wider one (24 pin I believe) and that’s the one I plugged in and that one isn’t blocked.

 

There are 2 connections labeled ATX. One has 16 pins and the other has 24. Since the power supply came with a 24 pin connector labeled CPU, I plugged in that one.

You were correct. I relooked and there are 2 separate connections on the power supply labeled cpu and each of them have 8 pins so if both are required to be connected to that 16 pin ATX connection on the motherboard then the Corsair H115 won’t work with my custom build. What a disappointment.

The power supply didn’t seem to come with a 16 pin plug but it did come with a wider one (24 pin I believe) and that’s the one I plugged in and that one isn’t blocked.

 

There are 2 connections labeled ATX. One has 16 pins and the other has 24. Since the power supply came with a 24 pin connector labeled CPU, I plugged in that one.

 

I'm well aware of what it is and what it looks like. I checked the reference material for your motherboard.

 

It's for 2 EPS +12V connectors, each with 8 pins. See http://www.playtool.com/pages/psuconnectors/connectors.html#eps8

 

It's not either these connectors or the 24-pin ATX connector. It's both.

 

A mainstream Intel CPU only uses 1 of them (8 pins). The X-series CPUs use 2 of them.

 

You can argue and debate it all you like. It still won't work without sufficient power. You can't even power a mainstream Skylake or Kaby Lake - much less a Skylake-X - without the additional CPU power.

the Corsair H115 won’t work with my custom build. What a disappointment.

 

Agreed. Your options at this point are to get a different cooler, get a different case or mount the cooler in the front like c-attack suggested.

I'm well aware of what it is and what it looks like. I checked the reference material for your motherboard.

 

It's for 2 EPS +12V connectors, each with 8 pins. See http://www.playtool.com/pages/psuconnectors/connectors.html#eps8

 

It's not either these connectors or the 24-pin ATX connector. It's both.

 

A mainstream Intel CPU only uses 1 of them (8 pins). The X-series CPUs use 2 of them.

 

You can argue and debate it all you like. It still won't work without sufficient power. You can't even power a mainstream Skylake or Kaby Lake - much less a Skylake-X - without the additional CPU power.

 

I’m neither arguing nor debating. I’m simply trying to understand something I’ve never done before. I realized after looking more closely that there are connections from the power supply that will plug into both connections labeled ATX in the mother board manual and if that’s what’s required then I’ll have to find another CPU cooling solution.

For top mount, you would have to live with a 240mm radiator (like the H100i PRO). However, I am not sure how much a like the 240 with the 7820X. It's not that a 240 cooler can't handle the default wattage, but you would probably wind up running the fans a bit hard, a bit too often. I would want a 280mm or 360mm.

 

I think the best immediate solution is to try the front mount intake behind the 3x120 and with the 2x140 mounted behind that. A lot of people have gone this route and as of yet, no one has come back and said it didn't work. This was a very frequent question prior the H150i Pro release (360mm). Now I think most people favor this from the start. That would be the other option in the front if you don't like the 120x3/140x2 push-pull idea.

Well mounting the fans on top would be more aesthetically pleasing. This PC isn’t going to be used as a gaming PC and there’s enough room for a 120 mm fan. I was wondering if one would be enough but from what you are saying even the 240 may be insufficient? Maybe then I have to go with your suggestion.

 

I’m just disappointed that Corsair didn’t factor in that added depth is necessary to accommodate cpu cooling and avoid impacting motherboard access.

One of the things I’m wondering about in your configuration recommendation is (and again, I’m learning this as I go along) I’m assuming the case fans will or might be running at different speeds than the cpu cooler fans since they’ll have different inputs so in some sense they wouldn’t necessarily be matched in terms of volume flow but I guess if it’s worked for others why not me.

Not insufficient. Possibly less than optimal for a working environment. I know people who run 5960X on a 120mm cooler and it "works". However, if you run regular renders or other professional type loads, you might need to keep the 2x120 on a 240mm radiator going pretty fast during the batch/job. On the other hand, the 2x140 or 3x120 on 280 or 360mm cooler will allow you to crank these out with the need the blast the fans, making staying in the room more inviting.

 

In the 3x120 + 280mm rad + 2x140 configuration, the interior 2x140 do all the work. You could unplug the 3x120 and it would still work. Because the 120s won't be a perfect fit on the radiator and line up slightly off, the fans do not exert a lot of influence over the airflow through the radiator. You don't need to keep them in sync and as long as you aren't running one set at max and the other at minimum, there should not be a be of lot interference. The only reason to do this instead of the plain old 2x140 front mount is to keep the 3x120 LED fan look in front. It is a signature element of the case.