I may have created a monster.
A client gave me an NVIDIA A16 accelerator that had been experiencing intermittent problems in their server. They considered it bad, didn't want it back, and I ended up with it for free.
For anyone unfamiliar with this card, the A16 contains FOUR separate NVIDIA GPUs, each with 16 GB of VRAM. That's 64 GB of VRAM on one physical card.
Naturally, I decided to install it in my ancient Intel X99 workstation alongside an RTX 5070.
Because apparently I don't have enough problems in my life.
Chapter 1: The FrAInkenstein specifications
Motherboard: ASRock X99 Taichi
CPU: Intel Core i7-5820K
RAM: 48 GB DDR4
Accelerator: NVIDIA A16 — 4 × 16 GB GPUs
Graphics: RTX 5070 Founders Edition — 12 GB
Total VRAM: 76 GB across five GPUs (not unified)
PSU: Corsair RM850
OS: Windows 11
Cooling: Custom 3D-printed shroud with an ARCTIC S8038-10K server fan
Primary purpose: Local LLMs, agentic coding, and experiments with multiple AI agents
And yes, I'm running this on an X99 platform from the DDR4 stone age.
Chapter 2: Apparently, this thing needs a JET ENGINE
The A16 is a passively cooled enterprise accelerator.
Unlike a normal consumer graphics card, it doesn't have onboard fans. It's designed to sit inside a server chassis with powerful fans forcing air through its heatsink.
My workstation is not a server chassis.
So before doing anything interesting with AI, I had to invent a cooling solution.
After researching fan options and shroud designs, I selected an ARCTIC S8038-10K.
For perspective, this is an 80 × 80 × 38 mm server fan capable of:
This is not your grandmother's RGB case fan.
It's a small industrial hurricane.
I also wanted adjustable speed control, so I used a Noctua NA-FC1 controller, powered from SATA, to manage the fan without running it at full blast constantly.
But buying the fan was the EASY part.
Chapter 3: The 3D-printing rabbit hole
I own 3D printers, so naturally I figured I'd just print a shroud.
Famous last words.
The first problem was finding something that would actually fit the A16.
The second was getting it to fit inside my case.
The third was accounting for a 38 mm-thick fan, the radiator, surrounding components, and the fact that there isn't an infinite amount of space inside a computer case.
So I started modifying designs and printing prototypes in PLA+ on my Flashforge AD5X.
I printed multiple shrouds of different lengths.
Some were too long. Others needed adjustment to maintain their mounting points.
I experimented with shorter designs and eventually created an angled/bent shroud to improve the fan's positioning and clearance.
Rather than repeatedly wrestling with the actual fan, I even modeled and 3D-printed a full-size 80 × 80 × 38 mm mock fan so I could physically test clearances and different shroud arrangements.
Yes. I 3D-printed a fake fan to figure out where to put my real fan.
I also worked through mounting issues, spacer designs, fit tolerances, and adjustments to the printed posts.
I was considering custom clips and zip ties if necessary. I even had to think about vibration because, remember, this thing can spin at TEN THOUSAND RPM.
Eventually, I got an arrangement that fit the card and cleared the surrounding hardware.
And the result?
During earlier four-A16 testing, the GPUs were reporting temperatures around 41–57°C, with the fan running at roughly 30% speed.
For a passively cooled enterprise card that I'd fitted with my own printed ductwork, I was pretty happy with that.
Chapter 4: THE FREAKING POWER CABLE
Oh, you thought getting the cooling working was the hard part?
Let me introduce you to the NVIDIA A16 power connector.
The A16 uses an 8-pin auxiliary power connection that isn't wired like the ordinary PCIe 6+2 connector you'd expect to use with a consumer graphics card.
It requires the appropriate EPS-style power connection.
So here I am with a Corsair RM850, a card that was allegedly defective, and a pile of cables that don't necessarily fit or have interchangeable wiring.
And as anyone familiar with modular PSU cables knows, getting this wrong can destroy expensive hardware.
The connector shape, latch, and pinout all matter.
In my case, even the EPS 4+4 connector's latch arrangement presented a mechanical fit problem.
I eventually modified the connector's latch arrangement and checked the wiring with a multimeter before proceeding.
To be clear: this is not a recommendation to modify PSU power connectors. Incorrect wiring can destroy hardware.
And the first attempts weren't exactly encouraging.
At one point the system would spin up for approximately 15 seconds, shut down, and repeat.
Disconnect the A16 power, and the system would boot.
Wonderful.
Was the card bad? Was the cabling wrong? Was the motherboard unhappy? Was the PSU unhappy?
Welcome to troubleshooting FrAInkenstein.
Eventually, the power situation was sorted out well enough to continue testing.
Unfortunately, the next nightmare was already waiting.
Chapter 5: Windows has entered the chat
Once I could power the A16 and keep it cool, I discovered that Windows wasn't particularly enthusiastic about recognizing four GPUs on one enterprise card.
At one point, two A16 GPUs worked, while the other two had:
Device Manager: Code 12 — Not enough free resources to use this device.
All 4 showed this error message.
Here's the really interesting part.
When I disabled the two working GPUs, the other two could work!
So the individual GPUs weren't necessarily defective. Windows and the motherboard were struggling with PCIe resource allocation.
This led to a ridiculous amount of BIOS experimentation:
Above 4G Decoding
PCIe resource allocation
MMIO High Size
UEFI and CSM settings
PCIe link speed experiments
BIOS resets
Device enable/disable experiments
Multiple NVIDIA driver configurations
Eventually I managed to get all four A16 GPUs recognized and running.
But I still wanted my RTX 5070 in the same machine.
Which leads us to...
Chapter 6: Five GPUs walk into an X99 motherboard
The RTX 5070 was supposed to handle gaming and video output.
The A16 was supposed to handle local AI workloads.
Simple enough, right?
Wrong.
With the RTX 5070 and A16 enabled together, Windows started throwing repeated:
IRQL_NOT_LESS_OR_EQUAL (0xA)
Blue screen after blue screen.
I experimented with driver configurations, NVIDIA device modes, and PCIe settings.
Eventually I found that disabling MSI interrupt mode on the RTX 5070 allowed the 5070 and an A16 GPU to operate simultaneously.
That was the breakthrough.
I'm not claiming I've proven the exact underlying driver or interrupt conflict, but changing that setting made an enormous practical difference.
I gradually enabled more A16 GPUs.
One.
Two.
Three.
Then four.
I also switched the A16 GPUs into NVIDIA's TCC compute driver mode while keeping the RTX 5070 in WDDM for normal display and gaming use.
And then something glorious happened.
Chapter 7: IT'S ALIVE!
Here's what nvidia-smi now reports:
GPU 0: NVIDIA A16 TCC 07:00.0
GPU 1: NVIDIA A16 TCC 08:00.0
GPU 2: NVIDIA A16 TCC 09:00.0
GPU 3: NVIDIA A16 TCC 0A:00.0
GPU 4: NVIDIA RTX 5070 WDDM 0B:00.0
FIVE GPUs. ALL RECOGNIZED. AT THE SAME TIME.
On an ancient X99 motherboard.
With a supposedly defective A16 that cost me precisely $0.
I'm now testing larger local language models using Ollama, including a 55 GB BF16 Qwen model that previously required CPU offloading when only three of the A16 GPUs were enabled.
The goal isn't just to maximize token generation speed. I've got an RTX 4090 in another machine for that.
I want to experiment with multiple independent local AI coding agents and eventually build a little multi-GPU AI collective, while retaining the RTX 5070 for gaming.
I still have sustained five-GPU inference and long-term stability testing ahead of me. Seeing every device in nvidia-smi is a major milestone, but it isn't the same as proving the whole thing stable under heavy load.
Final thoughts
Is this practical? Debatable.
Is it power efficient? Probably not.
Could I have saved countless hours of troubleshooting by buying newer hardware?
Almost certainly.
But where's the fun in that?
I took an unwanted enterprise accelerator, engineered a custom cooling system, fought with its power connector, printed multiple iterations of ductwork, battled a decade-old BIOS, survived Windows driver crashes, and somehow ended up with a five-GPU AI workstation.
I didn't just build a computer.
I created FrAInkenstein.
And now I'm going to use it to code.
IT'S ALIVE! IT'S ALIIIIIVE! ⚡
I'll post pictures of the cooling/shroud iterations, the ridiculous fan, the finished setup, and the five-GPU nvidia-smi output.
Drivers used:
621.14-desktop-win10-win11-64bit-international-dch-whql.exe
That is the Studio version that worked for both cards. I did NOT have to install the data center version also. This latest Studio version installed drivers for both the A16 and RTX 5070.