Thank you!

I'm working on a 2025 version of this article, and yes- I would not recommend the RTX 3090 or NVLink in 2025. When I wrote the 2024 article, the RTX 3090 was going for around $700 on eBay, and the 4-slot NVLink bridge was around $100. Today, they are ~$1,200 and ~$300, respectively, which means that two RTX 3090s would cost MORE than a single RTX 5090 (if you can find one for sale at MSRP).

While parallelizing training and inference workloads across both 3090s did provide a tangible performance gain (I would estimate around 1.7-1.8x), per benchmarks the RTX 5090 appears to be significantly stronger than two 3090s, while using less physical space and less electricity. Obviously, given the choice you would want to opt for a single GPU over a multi-GPU setup.

I'm still doing some research, but my leaning is that a much smaller desktop is the way to go, since the 5090 (NVIDIA's version) is only two slots wide rather than the six that two 3090s occupy. An added bonus is that you could use a consumer-level CPU rather than a Threadripper or Xeon.