🪛 Stats system (powered by WAS)

Don't confuse this with the resource monitor bar Crystools is best known for - the always-on CPU/GPU/RAM/VRAM readout it adds to ComfyUI's menu. This is a different thing: a small inline node. It takes a LATENT in, shows you RAM, VRAM, and disk space stats right on the node when it executes, and passes the same LATENT back out untouched so it can sit inside a sampling chain without breaking anything.

Why you'd reach for it

Drop it between two nodes that already have a latent flowing between them - right after a KSampler is the natural spot - when you want a stats snapshot at that exact point in execution, without restructuring your graph or branching off just to check memory. The README is explicit that it "should connect as a pipe," meaning it's meant to sit inline in the data flow, not dangle off to the side as a standalone probe.

How it works

Worth knowing where this actually comes from: per the pack's own README, the underlying logic isn't original to Crystools - it's credited to WAS Node Suite, and Crystian's version just adds the on-node display on top of it. Under the hood it leans on the same psutil/pynvml stack that powers the pack's headline resource monitor.

Inputs and outputs

One required input: latent. One output: latent - the exact same object passed straight through, so the node adds a readout without altering anything in your pipeline.

Installing it

Through ComfyUI Manager, search crystools. Manually:

cd ComfyUI/custom_nodes
git clone https://github.com/crystian/ComfyUI-Crystools.git
cd ComfyUI-Crystools
pip install -r requirements.txt

Restart ComfyUI. GPU stats specifically depend on pynvml, NVIDIA's own library - the README is upfront that GPU data is CUDA-only ("sorry AMD users"). On a machine without an NVIDIA GPU, or without CUDA visible to ComfyUI, expect RAM and space numbers but not much on the GPU/VRAM side.

Common issues

Because it requires a LATENT input, you can't drop this node just anywhere to check stats - it only fits at points in the graph where a latent is already flowing, which is a real constraint compared to the always-visible menu-bar monitor that works regardless of graph shape. If you want a stats check outside a latent pipeline, the menu monitor (a UI feature the pack adds, not a node) is the better tool.

More broadly, Crystools nodes have a documented history of breaking after ComfyUI frontend updates - users have reported the pack's monitor UI failing to load its CSS or vanishing from the menu bar entirely after upgrading to a new ComfyUI interface, usually fixed by reinstalling the pack so its assets and Python dependencies resolve fresh against the new version. If stats stop showing up anywhere in the pack, that's the first thing to check.