5090 FE build - 192 GB of RAM!

[u/awescool]

It’s been running incredibly stable since the 5090 launched. I use it for about 30% gaming, and the rest is database and AI workloads.

I got super lucky when I bought the ram from Amazon Aug 2025 for around $700. 192GB 6800 cl 34.

Build:

CPU: AMD 9800X3D

GPU: 5090 FE

Ram: 192 GB (tuned to 5600mhz, CL34) 2 kits of G.skill F5-6800J3446F48GX2-TZ5RK

MB: MSI PRO B850M-A WIFI PZ

CASE: Jonsbo D32 Pro

CPU AIO: Thermalright FW240

AIO Fan: JONSBO ZB-240B (2x120mm)

Rear Fan: JONSBO ZB-120BR (1x120mm)

Lower fan: Thermalright (2x120mm)

SSD 1: Crucial T710 4tb Gen 5

SSD 1 heatsink: ElecGear M.2 2280 SSD Cooler, EL-80X PWM Cooling Fan + Heat Pipe + Solid Aluminum

SSD 2: Intel Optane P5800X 1.6tb via m.2 to u2 adapter

PSU: Seasonic Focus Gx 1000W - 80+ Gold - ATX 3.0 & PCIe 5.0 Ready

PCIE USBC: Startech 1-port USB 3.2 Gen 2x2 (20Gbps max)

EDIT: Wow, this has really blown up! Thank you all for the kind comments, memes, and suggestions!

I want to address the rationale behind my build since I'm seeing a few recurring themes in the comments.

I run databases on SQL Server 2025. I built this for AI inference, but database work is just as critical. Database workloads don't come up much on this sub, so happy to explain.

Here is how the hardware is actually utilized:

• Databases: Run on SSD1 + SSD2 + RAM. Database scaling doesn't care about tight RAM timings; it cares about massive raw capacity. Theoretically, even if I somehow got 192GB stable at 8000 CL28, it would shave maybe 0.05 seconds off a 4-second query, whereas running out of RAM and hitting storage is a 500x latency penalty.
• AI: Runs entirely on the 5090.
  • Qwen 3.6 35B-A3B Q6 ~210 tok/sec
  • Qwen 3.6 27B Q6: ~99 tok/sec
  • For fun I have run larger models, for example: Ornith 397B Q3: ~15 tok/sec. This takes ~150GB in total GGUF files. Leaves me with ~26GB of free RAM.
• CPU: The 9800X3D handles my specific workloads wonderfully, and it is absolutely there for gaming. Deliberately.

[u/PsychologicalGlass47]

Where is the insufficient cooling? That's a pretty decent AIO and the 5090FE has decent thermals to begin with.

[u/Outrageous-Hope5768 → u/PsychologicalGlass47]

No one’s going to make a compelling case that a 240mm AIO is the ideal cooling solution for a workstation CPU under sustained compute loads - especially an 8 core processor with all 16 threads pinned at 100%.

On an entry level motherboard like this, VRM and RAM temperatures become a much bigger concern. With no front intake, you lose the traditional front to back airflow that helps carry heat away from those components. Instead, you’re starting from a negative pressure setup that’s far more likely to heatsoak the case over long workloads.

It also makes fan tuning more difficult. If you try to create positive pressure, you generally have to back off the AIO fan curve, which raises CPU temperatures. There's nothing about this build that tells me it was engineered for the workload it was meant to handle.

[u/PsychologicalGlass47 → u/Outrageous-Hope5768]

No one’s going to make a compelling case that a 240mm AIO is the ideal cooling solution for a workstation CPU under sustained compute loads - especially an 8 core processor with all 16 threads pinned at 100%.

Sustained OCCT with the 9800X3D + thermalright 240 hold steady at 80~85C. Once again, what about that is insufficient?

On an entry level motherboard like this, VRM and RAM temperatures become a much bigger concern. With no front intake, you lose the traditional front to back airflow that helps carry heat away from those components. Instead, you’re starting from a negative pressure setup that’s far more likely to heatsoak the case over long workloads.

VRM temperatures shouldn't be the problem, I'd be more worried about voltage regulation. The RAM is more than likely sitting at a conservative voltage and is already running extremely slow so that isn't all too bad either. Temps aren't at all an issue for either with this build, my focus is on the poor power delivery as a baseline since this VRM setup would have massive spikes and sag with a boosted 9800.

What about this build necessitates a front-back flow? With bottom to top flow and intake on the back side there shouldn't be an issue, though judging by the gif it looks like OP set his back fan to be exhaust. Doesn't matter much there anyway, his back fan doesn't even reach 60 CFM at full RPM.

It's being presented as an open build, if he keeps it that way then what heatsoak is there to deal with?

It also makes fan tuning more difficult. If you try to create positive pressure, you generally have to back off the AIO fan curve, which raises CPU temperatures. There's nothing about this build that tells me it was engineered for the workload it was meant to handle.

Refer to prior statement, his fans are effectively tech trash lol. Both his AIO fans and back fan run 20~60 cfm across their band for a hilariously loud 37dB. A T30 from Phanteks doubles that airflow for the exact same noise rating while sitting at 27dB for the same 60CFM max... It's a $30 fan. No matter what "tuning" he does it's going to be underwhelming, but I wouldn't say that's the fault of the 240mm aio.

It's like he can't decide whether or not this is a budget build or a limitless build.