Building a silent rack-mounted workstation with the Silverstone RM51

[tacitus]

I want to build a low-noise rack-mounted workstation. My current plan is to use the Silverstone RM51 case (specs and some photos below). I’m looking for guidance on how to optimize this build according to my goals:

— Low noise is a requirement for me because I do audio recording in the room where this computer will be.

— Rack mounting is a long-time dream of mine, in part because I have a lot of rack-mounted audio equipment and it would be awesome to have all of my gear, including my computer, in a single rack.

— I don’t strictly need high end CPU performance, although a strong CPU is nice to have for my audio production work.

— I want this computer to be ready to utilize a high-end GPU at some later point (for training and running AI models, so I would mainly be looking for a card with a lot of memory, e.g. 24 GB or more, not necessarily the fastest GPU).

— I am prepared to throw a bit of money at the case and cooling setup and I would be happy to err on the side of over-sizing the cooling.

The RM51 comes with two 180 mm intake fans pre-installed behind the mesh front panel, so that’s a good start. It has a slot for a 140 mm exhaust fan in the back. It also comes with an external fan cage which can be used to mount an additional two 80 mm fans in the back, above the expansion slots.

The case can fit a CPU cooler up to 181 mm in height and I would be happy to utilize as much as possible of that space and get a high-end cooler, maybe the Be Quiet! Dark Rock Pro 4. AIO water cooling is an option, as the 180 mm front fans can be replaced with a 360 mm AIO radiator. I don't think I am confident enough in my computer building skills to go for a custom water cooling solution.

Here are some question which I have a hard time answering despite many hours of research:

1. If I splurge on a high-end CPU cooler, high-end fans, a PSU engineered for noise reduction etc… How strong a CPU can I get away with and still have the computer be fairly silent with this kind of case? How should I reason about this to come up with an estimate?

2. As far as I understand, air cooling is probably my best bet for noise reduction, because the total number of fans moving air around would be higher and they would thus operate at lower RPM. But my understanding is superficial. Should I consider AIO water cooling to get noise down?

3. If I were confident enough to embark on building a custom loop liquid cooling system, could I get this computer even quieter?

4. Is the RM51 a bad choice? Maybe its thermal and acoustic characteristics are so inferior to e.g. high-end gaming cases, that I should reconsider the whole rack-mounting part? Maybe there are better rack-mounted options?

5. Are the pre-installed 180 mm fans (Air Penetrator 184i PRO) suitable for a silent build? Should I replace them, e.g. with fans engineered specifically for silent operation? Unusual form factor so not sure if there are any plausible alternatives?

6. If I later plug a high-end graphics card into this machine, how will it change the picture? Can I prepare for this scenario by making better choices from the beginning? (The PSU I have picked out so far is 850 W.) Is it unrealistic to have a silent computer with a 24+ GB graphics card in a case like this? Or is it just a matter of paying for a card with particularly good cooling or maybe underclocking the GPU?

Thank you in advance for any comments you may have for me!

Here are some details about (and photos of) the components I currently have my sights on:

Spoiler: Details

2 x 180 mm intake fans, pre-installed: Air Penetrator 184i PRO

0-1200 RPM
0-143.21 CFM
0-34.5 dBA

140 mm exhaust fan: Be Quiet! Silent Wings Pro 4 140mm PWM

0-2400 RPM
0-97.41 CFM
0-36.8 dBA

CPU cooler: Be Quiet! Dark Rock Pro 4

TDP: 250 W
dBA @ 50/75/100%: 12.8 / 17.9 / 24.3
Dual-tower design, 2 fans, both Silent Wings PWM, one 120 mm and one 135 mm



PSU: Be Quiet! Straight Power 11 850 W Gold

Case: Silverstone RM51

 

[don256us]

I'm not sure that I can address your questions in full but I will try to get this moving forward.

AIO water cooling from the front panel would not be my first choice. You're either going to bring air into the case to cool the rad. This is taking the heat of the CPU, bringing that heat up front then pulling air into the case after you heated that air up. Counter intuitive to me. Or, your pushing air from the back out the front keeping you nice and warm. Not ideal to me. Your opinion of that matter is what counts.

In terms of selecting hardware to install, start with low TDP CPUs. Find the CPU spec that you need, then compare TDP from all CPUs in that class or better. E.G. I selected an AMD Ryzen 7 5700x over the 5800x because the 5700x had a lower operating temp. Less to cool means that you can have more silence in coolers. Once you find your CPU, the rest falls into place. The CPU will determin the MB and RAM.

I water cooled many years ago but found that you still need good air cooling for everything that isn't the CPU. For that reason, I gave it up. I prefer large slow moving fans. The bigger the more CFM which means more cooling. Slower means less noise. So get the largest fans you can buy at the lowest dba. This is tricky though. The last time I went to find fan reviews, they talk a good game about silence but don't actually measure the volume. Go with big brand names that you trust and search reviews. With enough time, you can find fans with the most CFM for the least amount of dba. Also consider a fan controller to help out. Keep in mind, just because it's big, doesn't mean it's better. It can be big but if a crap design, it will be loud at all speed levels. Noctua are well known for good air pressure for low noise. Also note that not all fans are designed to be silent. Even Noctua makes fans that are just designed for high CFM with little concern for dba.

I would plan on setting the front fans to pull air in and the rear fans to exhaust air out. Plan on a HSF for the CPU that will compliment that air flow. You should try for a straight line from the front, through the CPU HSF and out the back. This will keep that heat from other items like the RAM and GPU. Since the BTX form factor never really caught on, RAM may always prevent good air flow but it depends on the MB you find. If you can find slots that go with your flow of air, then all the better.

80mm fans are generally known for being loud but again, it depends on how they're made. If they spin slow and have good blade design, they could work but I would use them as helpers to a 140 in the slot next to them. Don't rely on the 80mm fans and set them to spin slow. A good 140mm fan spinning slow with good fin design would be the primary exhaust for me.

An 850 watt PSU is plenty good for most GPUs today. Maybe even for a 4090 but a 4090 ain't silent. Since GPU speed is not your primary, stay away from loud power hungry GPUs and you should get the silence you need to record with.

 

[tacitus]

Thank you very much for you comments!

Since I posted the above, I went ahead and built the computer. I went for all-air cooling with the Be Quiet! Dark Rock Pro 4 and three case fans, the pre-installed 2 x 180 mm intake fans and an extra 140 mm exhaust fan from Be Quiet!. I also bought a PSU from Be Quiet!, the Straight Power 11 1000W.

I decided on the Ryzen 5900X. Based off test reports I found online I figured I could probably get away with it, and if not I figured I could underclock it to make it cool enough. For my entry-level graphics card (planning to upgrade eventually), I picked an RTX 3060, the Ventus 3X 12G OC from MSI, which has three 80 mm fans.

As it turns out, this computer runs very quiet with my normal workload (a DAW recording multiple channels, doing a fair bit of real-time processing of each channel and broadcasting the resulting mix). It's not completely silent, of course, but the noise is significantly lower than the preexisting unavoidable background noise in the room, e.g. faint sounds from at nearby road heard through a closed window.

I spent about 10 minutes tweaking the fan curves, without really reading up on that stuff beforehand, so there's probably room for improvement. Also, this is a Linux system, so I don't have the best tooling for testing and controlling fans in real time. I simply set fan curves in the BIOS, left everything else on default settings. Curious to try the pre-defined ECO mode to push the heat and noise even further down.

The Silverstone RM51 is a fantastic case. Bulky, of course, but the build quality is unbelievable. The Dark Rock Pro 4 wasn't hard at all to install (people warn about this online but I found it very straight forward). Some have reported disturbing noise levels from the Air Penetrator 184i PRO fans (2 x 180 mm front case fans) when run in PWM mode, possibly due to defective ball bearings, so I was anxious about that. But it seems they have fixed the problem in newer batches because the fans are very quiet in my computer.

All in all I am really happy with this new machine!

 

[EarthDog]

For years now, I've set all my fans to low and been great, even with flagship-class CPUs. That said, I buy AIO's and cooling with more capacity than air coolers, but, it's how I roll and wouldn't change for the world. That silence... never hearing fans ramp up.............yaaaaaaaaaaaaaaas, lol.

Glad your air cooled machine is quiet for your needs!!!

 

[Zerileous]

Glad it all worked out. I was going to suggest putting t he PC in a different room with a thunderbolt cable, depending on your noise floor. Also I'm not fresh on the details, but that CPU is supposed to respond really well to undervolting. I think a high power GPU will really throw off the silent thing, but if you're not using it at the same time as recording, maybe it doesn't matter.