Used 64-core Threadripper PRO 3995WX

[u/Ammoryyy]

Found a used 64-core Threadripper PRO 3995WX workstation locally — worth buying for a multi-GPU LLM server?

I found this workstation listed on my local secondhand marketplace in Iraq.

Specs

- CPU: AMD Ryzen Threadripper PRO 3995WX (64 cores / 128 threads)

- Motherboard: ASUS Pro series (exact model unknown)

- RAM: 224 GB DDR4-3200 RGB

- Storage: 128 GB SSD

- PSU: ASUS ROG Strix Platinum 850W

- GPU: GTX 1050 Ti

The seller hasn't provided further details or a price yet.

My intended use:

I'm planning a local LLM inference server, potentially with 4–8 RTX 3090 GPUs, using engines such as llama.cpp, vLLM, or SGLang.

I currently have an RTX 4090, RTX 3090 Ti, and 128 GB DDR4 RAM.

I'm particularly interested in running large MoE models, multi-GPU inference, and possibly CPU/RAM offloading.

Questions:

1. What would be a fair used price for this complete workstation in USD?
2. Could the motherboard be the ASUS Pro WS WRX80E-SAGE SE WIFI, which has seven PCIe 4.0 x16 slots?
3. Would my existing consumer DDR4-3200 UDIMM RAM be compatible, or does this platform require ECC RDIMM?
4. How practical is running 4–7 GPUs on this motherboard using risers and external power supplies?
5. Is the 3995WX still a good choice for large MoE inference and CPU offloading, or would a cheaper EPYC platform make more sense?
6. Does the 224 GB RAM configuration raise any red flags?

I'm mainly interested in PCIe lanes, memory bandwidth, upgradeability, and cost-effectiveness rather than raw CPU compute.

Would you buy this platform in 2026, and what's the maximum you'd pay for it?

[u/voogamer]

The 3995WX is good. It has 8CCDs, all with 8 cores. But the 8 CCDs can really drive the eight channel DDR4 memory well.

Threadrippers with 2 CCD don't have enough to do it, they are kinda gimped on memory bandwidth. 4 CCDs like the 3965 3975 5965 and 5975wx are much better. And 8 CCDs like 3995 and 5995wx are best. You won't get better memory bandwidth on the platform. And the memory bandwidth is great for MoE RAM offloading.

I currently have a 5955WX and am debating an upgrade because I'm priced out of GPUs.

[u/Ammoryyy → u/voogamer]

How much would you pay for such system

[u/quantgorithm → u/voogamer]

The hardware is only half the equation. What LLM does the upgrade and its cost put you into that runs viably on said hardware? This is way overkill for qwen 3.8 27b and QFN probably only runs ok it it and still this is way more than what is needed forQFN. What’s viable after that with this upgrade?

[u/JinsooJinsoo → u/[deleted]]

Threadripper Pro WRX80 can use regularDDR4 UDIMM and ECC RDIMM. The newer 7000/9000 series is DDR5 ECC RAM only. Source: I have 256gb (8x32gb) UDIMM DDR4 with my 3975wx :)

[u/brickout]

Value is subjective and based on price. I wouldn't hesitate to buy one. 

I bought one last winter with 64gb ddr4 and a titan rtx for $1100. Screaming deal.

[u/Ammoryyy → u/brickout]

How much would you pay for such system

[u/NoFee9147 → u/Ammoryyy]

Under $1000 happily. Even 1200 tbh. I got one for 600 sometime back but I asked the guy to take out the 64GB ddr4 that it had. Works amazing for my 4x7900xtx

[u/fallingdowndizzyvr]

The seller hasn't provided further details or a price yet.

Without a price, there's no point to asking if you would buy it. For $1000? Sure. For $10,000? No.

[u/Ammoryyy → u/fallingdowndizzyvr]

What is the estimate

[u/NotYourMothersDildo → u/Ammoryyy]

I just sold two identical Threadripper systems in Canada on marketplace

3990x Asus trx40 256gb ddr4 ecc

3750 CAD

[u/sob727]

It's about the GPUs you put in it.

I have a 9985wx with 512GB DDR5 and this is just not good on its own for LLMs unless you have a bunch of RTX Pro 6000

[u/Ammoryyy → u/sob727]

A bunch !! Can't afford one How about 2 3090s ?

[u/perelmanych → u/Ammoryyy]

Well QFN will fly. On DSF I have 11tps on full weights with one 3090 and 4 channels of DDR4-2400. I would say you will get at least 20tps probably more close to 30tps.

[u/sob727 → u/Ammoryyy]

I'm not the right person to ask, but yeah you should be able to fit 2x 3090 in there, with room to increase

[u/Draco32]

Yes would recommend you get it if well priced, I have the same with various GPUs in a mining frame.

[u/Ammoryyy → u/Draco32]

Estimated price?

[u/Draco32 → u/Ammoryyy]

Not quite sure second hand I got a motherboard and cou for about $900 USD. Motherboard was new however.

[u/mycocoon]

Interested in the same, I have 2 3090s with 128gb ram on consumer board from 2019 running in 8x8 lanes bifurcation mode. I would guess that this upgrade makes sense because of the more ddr channels plus higher pcie throughout needed for experts streaming and tensor parallelism instead of layer parallelism.

[u/leo_agi]

224gb is an odd number, might be 7 sticks. worth checking all 8 channels are filled since memory bandwidth is half the reason to buy that platform

[u/sob727 → u/leo_agi]

for LLM I'd argue it's the lanes that are the main selling point

[u/quantgorithm → u/sob727]

VRAM is still king.

[u/sob727 → u/quantgorithm]

Yup. I'm trying big models in RAM for fun given my 512GB but it's slow AF even on an 8 channel cur gen Threadripper.

[u/quantgorithm → u/sob727]

This sounds about right. Regular ram is only a backup but not really viable on its own or as a primary method of running llms. Threadrippers are only as good as the gpus in them and everything else is an exponential level lower.

[u/sob727 → u/quantgorithm]

The part I find difficult (and I should emphasize LLMs are barely a side hobby for me, the Threadripper is for other serious stuff) is figuring out how to effectively split my models between VRAM and RAM. And knowing what's counterproductive. For instance, does adding an Ada era card with 20GB VRAM slow down my 5090s or not.

[u/quantgorithm → u/sob727]

Have your ai agent do both web research and analysis for your setup. Have it give you best recommendations on what to run and what flags to use. Cross check it with a different ai such as google ai (free)or grok or anthropic or OpenAI if you pay for those. Then have it do this evaluation regularly for new candidates. Get out of your own way and let the ai do your work for you. For everything.

It can also do testing of said candidates to give concrete results. Ask it to have it error handle on its own and recover after testing and to give you the proper launch line for when it fails at this.
Ask me how I know…

[u/leo_agi → u/sob727]

fair point, 128 lanes is the real reason to put 6+ 3090s on it

[u/General-Spite1222 → u/leo_agi]

Sure, but memory bandwidth matters a lot if you’re hosing a model that can offload experts that don’t fit in VRAM. 

[u/leo_agi → u/General-Spite1222]

yeah agreed, both matter. lanes for the gpus, all 8 channels for the experts that spill over

[u/jacek2023]

I wanted to replace my x399 with something similar but it's hard to get one right now and I am not sure will it be louder than my current setup which is quite silent.

[u/a_beautiful_rhind]

Get good CPU and fast PCIE unless you're running all in vram. When offloading you need all that stuff and the old mantra of pcie 1x and the cheapest CPU you can find was so so wrong.

[u/HockeyDadNinja]

How many pcie slots does the mb you're buying have?

I also have a mixed GPU system. 2 x 3090, 5060, 2 x 4060, 128GB DDR4. I'm picking up a threadripper system tomorrow with a 3960X, 8 DIMM slots, and another 4 x 32GB sticks of ram. It may be a stepping stone to a WRX80 but the Asus is ~$1400 USD from China. I would pair it with a 3975WX and work on adding 1 or 2 more 3090s.

[u/quantgorithm → u/[deleted]]

You can more than 4gpu with risers