SilverStoneRM42-502 4U rackmount Server Chassis with Liquid Cooling Compatibility, SST-RM42-502

Great upgrade 4U case for my home lab cloud server. I needed more room to add a RTX-5090 to this rig, and didn't want to go all the way to a 5U case. To be clear, there is only one 5090 card brand (Zotac) that will fit this 4U case with enough room on top to comfortably fit the 600W connector & wiring. If using another brand, I would probably go with a 5u case. I installed the Zotac Solid OC specifically in this build. Other Zotac models will likely fit as well. The SOLIDs 137mm height is a perfect fit for this case (which specifies a154mm max height). The case came with a number of front GPU support brackets. I used one, and it makes for a very solid mount. The 5090s aluminum frame holes at the front of the card lined up perfectly with the holes in the provided bracket. With the card secured with three screws in the back, and the case bracket in the front, I am confident the card will not come loose when removing/installing this case in my rack.As far as cooling, the case will fit one Noctua NF-A14x25r G2 PWM (140mm) and two NF-A12x25 PWM (120mm) in the front panel. It is tight, but can be done. Use the adjustable slots instead of fixed holes to slide the two 120mm fans far to the left and right sides of the case to leave room for the 140mm in the middle. I loaded this case up with a total of 8 fans (added a custom slot bracket with (2) 40mm fans for a total of 7 case fans and a Noctua NH-D12L CPU cooler w/fan). This configuration provides fantastic airflow and dropped the CPU temp by a solid 20C over the previous 2U case which was cooling challenged even with a Ghost S1 CPU cooler and (4) 80mm case fans.. Overall well made case. Even with a 10G NIC card and the RTX 5090 installed, there is still room to access at least 2 of the SATA 2.5" mounting plates comfortably (no wires/cards in the way). I now plan on adding a couple of large SATA drives in raid mirror as a home network file server and for backups, making this machine even more of a Swiss army knife of a server. This combination of fans is almost completely silent, even with a moderate load. With the fans at 100% it is only noticeable if you are in the same room, but I doubt you would hear it in the next room. Overall very happy with this case.One negative ,but not enough to remove a star, the manufacturer does not sell a set of sliding rails that fits this case in short racks (slightly less than 22" deep). This case uses screwless rail studs to connect the rails, and there is no option for screw on rails. The only rails designed for this case are too long for my rack. I ended up using the Cyber Power 4POSTRAIL, which worked, but is VERY tight when sliding in the heavy duty rack ears on this case. Installer trick, don't lock down the rail mounting screws (just hand snug them). After you slide the case in fully (might take some wiggling), lock the back screws and the bottom two screws in front. This will lock the rails in place with perfect spacing/alignment, then you can pull the case out and lock down the top two front screws.

Pros:1) Only NAS chassis I'm aware of with 12 hot-swappable drive bays + 120mm to 360mm radiator support. Most other chassis either give you a lot of drive bays with limited CPU cooler support, or have a wide range of CPU cooler support, but limited drive bays.2) Built like a tank. I don't have this in a server rack mount, so its been taking its fair share of beating when I've had to move it around, but its sturdy as hell.Cons:1) Built like a tank. This thing is heavy even without all 12 bays populated...2) Very sharp corners and panel edges. I hope SilverStone takes some time to find ways to round off the sharp corners and panel edges. I can see someone cutting themselves when rotating this around for maintenance since its already so heavy.Other Notes:Someone else mentioned that the 3 OEM 80mm x 15mm hard drive fans are noisy. They are. According to the manuals the default fan profile when the fan headers are plugged into the backplane is drive temps >= 45C means 99%-100% fan speed. 12 fully populate bays will mean your drives will be 45C or more, so I wouldn't recommend using the backplane fan headers unless you like your fans always at basically 100%I did try a bunch of different brands of fans to test out, and the OEM fans are probably the best 80mm x 15mm fans to have in terms of noise to cooling capabilities.I tried 3 Noctua NF-A8s (80mm x 25mm) mounted behind the backplane bracket towards the PSU (compared to the OEM fans being mounted in front of the backplane bracket towards the backplanes), and while those were definitely quieter they could not sufficiently cool down twelve 3.5in drives without being on 100% speed (and at that point you can definitely hear them).If you want to mount 80mm fans from other brands in the same orientation as the OEM fans then you can get away with anything up to 80mm x 20mm. Otherwise you can go up to 80mm x 25mm without issues when mounting the fans behind the backplane fan bracket towards the PSU.You can technically go as deep as 80mm x 38mm when mounting the fans behind the backplane fan bracket instead of the default OEM orientation, but you may run into some issues with thread holes from the mobo preventing flush mounting of your fans.I settled on 3 Sanyo Denki 9GA0812P1H611 80mm x 38mm fans (mounted slightly crooked) at 6% - 14% duty cycle. That is sufficient for keeping all 12 drives between 38C and 45C during heavy drive loads while keeping the noise as low as possible.