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Crystal 680X RGB Build Check


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First time builder here, and I’ve gone straight for the deep end. Just want to be sure I’m understanding the organization of the RGB fan cables correctly. I haven’t chosen my exact motherboard yet because I’m still trying to make sure I have the right headers etc.


My planned build is:

Case: Crystal 680X (Black)

PSU: RM850x (A bit high I think but I was given one already)

CPU: Ryzen 7 3700X

MoBo: (Prime X570-Pro / MEG X570 Unity)

GPU: RTX 2070 Super FE

RAM: 32gb Corsair Vengeance RGB 3200

Storage: 970 EVO m.2 1TB

Fans: 7x LL120, 1x non-RGB fan included with case

+2x fan controllers and Commander Pro


So first I just wanna see if I’m getting the organization right, I have read over the main how-to thread but I just wanna see if I’ve got it set up correctly. I have included a crude diagram similar to that on the other page with color coded fans. Basically the fans go in sequence and are connected to the RGB controllers and then to the commander (instead of 4pin headers on MoBo, with the use of two 1to2 splitters which would have two fans running together each), and the RGB controllers are connected to the commander via USB, then the commander and controllers are all connected to PSU via SATA, and the command is connected to the MoBo via internal USB. Is that correct? For a MoBo with a JCORSAIR1 slot, does that take the place of the USB? I plug the USB into the JCORSAIR1? Sorry to ask a redundant question it’s just the diagram on the main guide says “SATA power”, which I assume means the PSU, I just want to be sure I’ve got the cords etc.


I have one other question (although if anyone see anything else starkly wrong with that build do please let me know), which concerns RGB headers on the MoBo. The 3700X fan (AMD Wraith Prism) is supposed to go into a USB and a 4pin RGB if I understand it correctly, so if I’m using the JCORSAIR1 header for Corsair fans and have 1 USB header free, or have at least two internal USB headers (I’m assuming no other parts need them as of now), I should be okay for the USB hookups, but one of the MoBo’s I’m looking at is the MEG x570 Unity which only has 3pin RGB headers, I know that’s not a corsair product but could that go into one of the Corsair controllers? Or is there a way to make use of a 3pin via converter of some sort?


I can wrestle with that if it’s not the right place to discuss it, but I would appreciate it if anyone can look at my fan setup or build and give it a thumbs up or tell me what I have overlooked etc. Thanks in advance, excited to take the dive into both PC building and Corsair RGB fans.



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You won't be using any of the motherboard headers, fan control or RGB, so you can decide on that based on other factors. It is possible to connect strips or a string of fans that will act like a long LED strip to the Jcorsair headers, but this puts the controls on the motherboard software side, drastically reduces your lighting options, and you are still going to need to run the iCUE control software for Corsair anyway, so there is no gain on any front.


Your USB 2.0 connections will carry data between software and devices through the motherboard. There have been quite a few people who have run into issues with the x570 chipset and USB connection stability (disconnect-connect-disconnect-etc). My advice is to plan on using a powered USB 2.0 hub from the start. It seems to help with this issue and most motherboards don't have very many 2.0 headers, so this solves two problems. You can find inexpensive ones for less than $20. A lot of x570 owners go with the NZXT version, but I am sure others work as well.


On the diagrams, the connection between the RGB Lighting hubs (where the fan lighting wires go) back to the Commander Pro will not be USB, but a proprietary lighting cable that goes in RGB Channel 1 and 2. Those will come with the LL multi-packs. That also means you will have those USB 2 pass through headers on the Commander to use for other needs.


All fan lighting wires will go to the RGB Lighting Hubs. All fan 4 pin PWM standard speed control wires will go to the Commander Pro fan ports. You can use splitters for those, but we recommend you keep it to dual splitters. Some triples work. Some do not.


The trickier bit with the 680x and 740 cases is the natural 7/8 fan layout. For fan control, the Commander can handle this. Lighting is trickier. In your diagram, you properly list two RGB Lighting Hubs with their 6 fan maximum. You can break the 8 fans up on those two any way you like (4+4, 6+2, 5+3), but understand that each will then act like its own lighting system. There are some effects that will go from Channel 1 start to end to Channel 2 and on, but most will start over back at fan 1 after it finishes the last one on that channel. This makes which fans you group together somewhat important for the possible lighting sequences. If put the front, top, and rear together, they will act as one series. The bottom two fans will act like a 2 fan system. The only other option is to use 3rd party lighting splitters, but there are limitations for current and there may not be an obvious way to pair some of them off. I am struggling to find a natural way for that case. I have the similar issue in my 740 with the same internal layout. I have split mine 4+4 top/bottom (with a false 4th fan on the bottom circuit). This is easier for my all 140mm layout with two fans on each panel. Hard to split up the front 3 and it's natural to want them to run together.

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Thanks a ton for the info, I really appreciate it!


So with the commander and iCUE, I plug the commander unit into an available USB 2.0 header on the board rather than the JCORSAIR header? I should have two 2.0 headers on the board, so if I just need one for the whole Corsair setup that’s great, and I can even use the second for the Wraith Prism, unless you were saying I plug that into the Corsair system too? As of now those are the only two things that I’ll have using USB internally so I think I’ll be able to use the ports on the back for USB drives etc. . . . unless any other core parts need an internal USB link I’m not aware of?


I’m not really concerned with the sequences for lighting effects with patterns etc., i’ll probably just use static colors and use the system more to customize the running speed of the fans, so I’m okay with the channel issue, but thank you for clearing that up! Do you recommend splitting the RGB load on the different channels or is it okay to fill one before moving on to the next (again I’m not so concerned with effects in sequence, just changing solid colors and fan speeds)? And thank you for the advice about maxing 2 fans, I do indeed plan on putting only 2to1 so in total I’ll have eight fans, with two pairs of two.


Again thank you for the in-depth help, I appreciate it and feel like I’ve got a clearer idea of how it all works. Now I just need to get this case. Had two places from Corsair’s alternate vendor list accept my order and then cancel it after a few days, and Corsair won’t respond to my inquiries, so I’ve had to order one from overseas which I hope will arrive intact. If it all works it’ll be cool to have at least some lighting fun even if the channels give me issues running the sequences, and above all I’m looking forward to keeping my system extra cool with so many fans and a very clean interior!


Thanks again!

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The JCorsair connection is not USB, but effectively a "lighting channel". It will have a flat connector like what goes from a RGB lighting hub to Lighting Node Pro or Commander Pro. Remember, this moves the control off the Corsair system and to the motherboard's interpretation of how things work. You only do this when you have one item to control and no other reason to run iCUE. You will have several. You don't want to use the Jcorsair header.


You theoretically can put the Wraith's USB connector into the C-Pro pass through. However, I would probably connect it directly to the other MB USB 2 port on an AMD board.


I don't know what's going on with 680X supply. There are none where I am either. Not sure if this is related to global events disrupting manufacturing and shipping or if my dreams are coming true and we are getting a larger version as a replacement. I would bet on the first.

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