# Inside an NVIDIA GB300 NVL72

How an NVIDIA GB300 NVL72 rack packs 72 AI GPUs into one cabinet, cooled by water and linked by copper, with power delivered through a busbar\.

By clever\-otter\-e563a014

Topic: Computing, AI & Electronics

[Open the interactive Jig](https://ask.jig.com/j/uz5jwmLFNNr9)

## Transcript

### 1. A supercomputer in one cabinet

This tall black cabinet is an NVIDIA GB300 NVL72 rack\. It holds 72 powerful chips called GPUs, the kind that train and run AI\. Fully loaded it weighs about 1\.5 tonnes, as much as a car\. Drag anywhere to look around it\.

GB300 means Grace CPUs paired with Blackwell Ultra GPUs\.

### 2. Stacked like trays in a bakery

Inside, flat metal drawers called trays slide in on rails, one above another\. Amber power shelves sit at the top and bottom\. Blue compute trays hold the chips, and green switch trays in the middle connect them all\.

This build: 18 compute trays, 9 switch trays and 8 power shelves\.

### 3. Slide out a compute tray

Each compute tray is a whole computer less than 5 centimetres tall\. Press the button to slide one out on its rails, with its lid off, and look inside\.

### 4. Two superchips under copper

At the back of the tray sit two superchips\. Each joins one Grace CPU, the organiser, with two Blackwell Ultra GPUs, the number crunchers\. The copper plates on top carry their heat away\. Four GPUs in each of 18 trays makes 72\.

Every GPU has 288 GB of super\-fast memory right beside it\.

### 5. Cooled by water, not just fans

Chips this busy get hot, so water does most of the cooling\. Cool water \(blue\) flows in at the back, through the copper plates, and leaves warm \(red\)\. The small fans only cool the drives and smaller boards\.

About 90% of the heat leaves in the water, even when it arrives as warm as 45 °C\.

### 6. The NVLink spine

Around the back, cable cartridges hold thousands of copper wires\. They link every GPU to the nine switch trays in the middle; green pulses show data on the move\. Any GPU can talk to any other at full speed, so all 72 work like one giant GPU\.

Together these links can move 130 terabytes every second\.

### 7. Power down a copper bar

The power shelves turn the building’s electricity into 50\-volt direct current\. A thick copper bar called a busbar carries it \(amber\) to every tray\. The whole rack can use about 135 kilowatts, roughly what a hundred homes use on average\.

### 8. One giant GPU

Power in, water through, and every chip linked by copper: that is the NVL72\. Data centres line up rows of these racks to train and run the AI tools people use every day\. Drag to explore it once more\.