I built Lambda's 4-GPU deep learning rig for $4000 cheaper

This is a follow-up to the previous post "I built Lambda's $12,500 deep learning rig for $6200" which had around 480 upvotes on Reddit. That previous build had only 3-GPUs and took some shortcuts. In response to the hundreds of comments on that post, including comments by the CEO of Lambda Labs, I built and tested multiple 4-GPU rigs. I'm back to share a near-perfect 4-GPU deep learning rig with the highest performance and reliability, no thermal throttling, and lowest cost. This build is nearly identical to Lambda's 4-GPU workstation, but costs around $4000 cheaper. Happy building!