SilverStone Technology RM51 5U Rackmount Server Chassis with Dual 180mm Fans and Enhanced Liquid Cooling Capability, SST-RM51

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.

Fantastic build quality like always from Silverstone. Just finished moving my Unraid server to this chassis. Here are a few notes for those who are doing the same. The included 80mm fans in the 2U portion of the chassis behind the backplanes are 15mm and not the standard 25mm. I bought some Noctua AF8s, but I had to mount them on the opposite side of the fan rail to have enough clearance. While that works, you then take 25mm of clearance away from the PSU area, which in my build was a real problem since my 1600W PSU was now too long to fit. I purchased a Corsair Shift 1200W PSU to relocate the cables to the large, open area normally used for a secondary PSU. Not a complicated problem to address, but I wasn't planning on having to buy a new PSU because of fans. I am happy that I stuck with the thicker Noctuas, though, because my HDDs are already running pretty warm in here. 45-48c are the hottest ones in my array (WD 10TB Red Plus 7200 rpm). The backplanes have fan headers and preset curves based on ambient temps. My ambient temp is 74F so it's not enough to speed the fans up enough to keep the drives below 45c which triggers the default Unraid alerts.This case does come with mounting rails, but they are not sliding, which is a shame for a case that is over $1,000 after tax.The dust filters are great, and the panels are nice and thick. I would have liked to see a flared edge on the end of the top and bottom panels towards the back to assist with sliding them on and off.Comes with all the accessories you need to slide and mount additional 5.25 bay devices (like for even more HDDs), which was a nice touch. The 4U top area has unobstructed airflow, and the three 120mm fans (not included) will blow straight across your motherboard and devices. It is a shame that this portion of the chassis wasn't 5U or 6U. Being limited to small air coolers that use 92mm fans means more heat, smaller fans, and more noise, and less overall performance. In my case, I had to move from a Noctua NH-U12 120mm tower cooler for my 2990WX Threadripper to an NH-U8 4U form factor cooler.Overall, I am extremely happy with my purchase. Thank you Silverstone for a great quality case.

I like the case, but it arrived damaged TWICE. The drive sleds do not seem to ship well- they can pop open during shipping and in my case this caused the black front plastic of the sled to snap off. I ordered another chassis and it too arrived with multiple sleds not not latched in place, and again, one of them was broken in the same way. That’s two $1100 server cases damaged on arrival back to back. Not a good sign! I think Silverstone should reconsider their packaging and find a way to make sure drive sleds don’t pop open during shipping.

This thing is rad. I wanted to put my gaming pc into my server rack and this thing was able to fit my RTX 4090 and iCue Link Titan 360 water cooler with room to spare. I was worried about heat, but so far so good on the temps. I did replace everything with Noctua fans to keep things quiet. I did have to do a little modding of the case to get the radiator to attach to the included water cooling bracket, but it was easy. Paired with Silverstone server rails, the installation into the rack was easy and the fit is perfect. It slides like glass. The only thing I don’t like is the front LED activity lights are waaaaay too bright. But you don’t have to connect those to the mobo if you don’t want to. Other than that, this case is awesome.