The usual blocker to learning GPU programming is hardware. The official guides assume you have a CUDA-capable NVIDIA card, a working toolchain, and a Linux box to run it on. So most people who are curious about how GPUs actually work never get past the setup.
Here is the thing: the hard part of GPU programming is not the hardware. It is the mental model. And you can learn that model without a GPU at all.
What you actually need to understand
GPU programming is about expressing a computation as thousands of tiny, identical tasks that run at the same time. The concepts that matter are:
The execution model: threads grouped into blocks, blocks into a grid. A single kernel runs across all of them at once, and each thread works out which piece of data it owns from its index.
Data-parallel thinking: turning a normal loop into "one thread per element." Map, reduce, and scan are the building blocks.
The memory hierarchy: global memory is large but slow, shared memory is tiny but fast. Almost all real GPU performance work is about moving data into fast memory and reusing it. Tiling a matrix multiply is the canonical example.
The patterns: parallel reductions, tiled linear algebra, and why some algorithms map beautifully to a GPU while others do not.
None of that requires the physical card to learn. It requires writing the kernels and reasoning about which thread touches which data.
Learn it by simulating it
The approach that works is to model the CUDA execution model in code: assign each "thread" its index, have it compute its slice, and watch how the pieces combine. When you implement a parallel reduction yourself, or tile a matrix multiply to reuse shared memory, the model stops being abstract. You feel why a memory layout is fast or slow.
Once the model is in your head, moving to real CUDA C on actual hardware is a syntax change, not a concept change. The thinking is identical.
Where to start
The GPU Computing track teaches exactly this. You work through the parallel and CUDA execution model, data-parallel patterns, the memory hierarchy and tiling, tiled linear algebra, rasterization, ray tracing, and an N-body simulation, building each one and running it in your browser. No GPU, no toolchain, no setup. The first project is free.
If you have been waiting until you "get a good GPU" to learn this, stop waiting. Learn the model first.