I’ve been saving up for a year and change for a GPU upgrade, and my local Microcenter finally had 5090s in stock. So I bought one. It is a CHONK – I’m getting full “you vs. the guy she tells you not to worry about” vibes:
![]() Top view comparing 3090 and 5090 (5090 is larger) | ![]() Side view comparing 3090 and 5090 (5090 is larger) |
Specifically, I’ve upgraded from a PNY RTX 3090 XLR8 Gaming EPIC-X RGB (what a mouthful) to a PNY RTX 5090 OC. Some of the size difference is due to “reference” vs “custom” PCB and cooler design; the 3090 is a reference design while the 5090 is a custom board and cooler. And it needs the cooler – the card now pulls up to 1.7x more electricity at up to 600W (no wonder Nvidia has problems with cables melting)! Regardless, I watercool the GPU in my system, so the size of the cooler shouldn’t matter (that assumption will come back to bite me in the ass).
| Feature | PNY GeForce RTX 3090 XLR8 Gaming EPIC-X RGB | PNY GeForce RTX 5090 OC |
|---|---|---|
| GPU Architecture | NVIDIA Ampere | NVIDIA Blackwell |
| CUDA Cores | 10,496 | 21,760 |
| Base/Boost Clock | 1395 / 1695 MHz | 2017 / 2527 MHz |
| Memory Size | 24 GB GDDR6X | 32 GB GDDR7 |
| Memory Speed | 1219 MHz | 1750 MHz |
| Memory Interface | 384-bit | 512-bit |
| Memory Bandwidth | 936 GB/s | 1792 GB/s |
| Transistors | 28.3 million | 92.2 million |
| TDP | 350 W | 575 W |
| Power Connectors | 2 x 8-pin | 16-pin (adapter to 4x 8-pin) |
| PCIe Interface | PCIe 4.0 x16 | PCIe 5.0 x16 |
| Outputs | 3 x DisplayPort 1.4, 1 x HDMI 2.1 | 3 x DisplayPort 2.1b, 1 x HDMI 2.1b |
| Dimensions | 11.57" x 4.41" x 2.2" (3-slot) | 12.95" x 5.43" x 2.8" (3.5-slot) |
The neat thing about these graphics cards with 24GB+ VRAM is that they can run super-capable LLMs locally. Models like Qwen 3 30B A3B, Qwen 3 32B, and Gemma 3 27B match or outperform proprietary models via paid API; the 5090’s token evaluation rate (which impacts experienced user latency) is also roughly equivalent to that experience via paid API. So I now have a local, private LLM instance that is functionally equivalent to GPT-4o or Claude 3.7 Sonnet! Granted, I’d have to have send on the ballpark of a quarter-million prompts to my self-hosted model to recoup the cost of the GPU instead of just using a paid API… but the upgrade was not intended to be a “cost saving” measure.

Qwen 3 30B A3B, Qwen 3 32B, and Gemma 3 27B match or beat proprietary models
60% Performance Improvement
After testing, I can confirm that the 5090 is faster. 🚫💩🕵️♂️ – it’s 2 architecture generations (Ampere -> Ada -> Blackwell) and 5 years (2020 -> 2025) / card generations (30xx -> 30xx Ti -> 40xx -> 40xx Ti -> 40xx Super -> 50xx) newer.
I tested with aidatools/ollama-benchmark, a very convenient command line benchmark based on Ollama that tests throughput over a variety of LLM and VLM architectures and sizes.
LLM Benchmark Results: RTX 3090 vs RTX 5090
| Model | Avg Eval Rate (RTX 3090) | Avg Eval Rate (RTX 5090) | Speedup (%) |
|---|---|---|---|
| mistral:7b | 133.51 | 210.89 | +58.0% |
| phi4:14b | 70.43 | 117.65 | +67.0% |
| gemma2:9b | 90.74 | 137.50 | +51.5% |
| llava:7b | 140.09 | 220.81 | +57.6% |
| llava:13b | 86.10 | 141.24 | +64.0% |
| deepseek-r1:8b | 111.83 | 181.26 | +62.1% |
| deepseek-r1:14b | 64.88 | 105.83 | +63.1% |
The benchmark indicates the 5090 has roughly 60% performance improvement over the 3090; the increases are larger as model size (parameters) increase. As the models used get even larger, I anticipate an even greater performance lift for the 5090, as a result of more tensor cores, more efficient tensor cores, and higher memory bandwidth; as the total utilization of the available compute/memory bandwidth approach 100%, the 5090 should increase its lead over the 3090.
System Specs
My PC is in an Alphacool 4u server chassis that supports water cooling; this lets me keep noise down, have quite good cooling performance, and I can stack my computer in a server rack with the rest of my homelab gear. For the non-nerds, this means that my computer is functionally “on its side” whereas a normal PC stands tall.

Gratuitous water cooling
You may notice the graphics card (top right, with “CORE” in shiny silver) is horizontal. This is because the 5090 is too big for the chassis, especially with the protrusion on the water block for connecting the water lines. So I had to hack the case with a “vertical GPU mount”; since the chassis is “on its side” relative to a normal computer, this means that the “vertical” mount lets me hold the card horizontally.
System Specs| Component | Specification |
|---|---|
| Motherboard | Asus ProArt X870E-Creator Wifi |
| CPU | AMD Ryzen 7 9800X3D |
| RAM | 64GB GSkill F5 DDR5-6000 (2x32GB) |
| Storage | 1TB Sabrent Rocket 5 |
| GPU | PNY RTX 3090 XLR8 REVEL EPIX-X -> PNY RTX 5090 Overclocked |
| PSU | Seasonic PRIME PX-1300 |
Watercooling components all Alphacool (not sponsored, I just find their stuff to be no-nonsense and effective):
- 60mm thick 360mm radiator
- 25mm thick 360mm radiator
- Alphacool TPV tubes, fittings, and quick-disconnects
- 3x Arctic S12038-4K fans (120 x 38mm)
- 3x Noctua NF-A12x25 Chromax fans (120 x 25mm)
Blogumentation
Here are my notes on configuring my system for the experiment:
1. Install WSL (Windows Subsystem for Linux)
- Install WSL, reboot
- Install distro (I use Debian)
- Configure distro (Create user account, etc.)
2. Install dependencies (in WSL)
Install standard dependencies
apt install curl wget git software-properties-common build-essentialCUDA for WSL
Install nvidia cuda-toolkit
⚠️ DO NOT INSTALL THE DRIVER ON WSL; ONLY INSTALL THE CUDA-TOOLKIT ⚠️Check GPU device post-installation using the compiled deviceQuery binary
apt install cmake mkdir build && cd build cmake .. make -j ./deviceQuery
Install ollama
curl -fsSL https://ollama.com/install.sh | shInstall pipx
apt install pipxInstall uv
curl -LsSf https://astral.sh/uv/install.sh | shInstall Docker Desktop
Install nvidia container toolkit - I did this, but I’m not sure whether it is necessary for this particular experiment
3. Install aidatools/ollama-benchmark
pipx install llm-benchmark4. Run tests
Close all apps
Disable internet
Run:
llm_benchmark run
Cite this article
If you would like to reference this article, please consider citing it as:
Graber, A. H. (2025, May 25). New GPU!. AI/MLbling-About. https://aimlbling-about.ninerealmlabs.com/blog/gpu-testing/Or with BibTeX:
@online{graber2025_gputesting,
author = {Graber, },
title = {New GPU!},
year = {2025},
date = {2025-05-25},
url = {https://aimlbling-about.ninerealmlabs.com/blog/gpu-testing/},
urldate = {2026-08-16},
note = {Blog post}
}

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