Arithmetic intensity
Arithmetic intensity is the number of arithmetic operations performed per byte transferred across a specified memory boundary.
How it works
Reusing a loaded tile increases work per byte at the lower memory level. Fusing operations can avoid intermediate writes and reads. Count useful arithmetic and actual traffic consistently, including the inputs and outputs needed by the stated operation.
Work through an example
A simple FP32 vector add reads two four-byte inputs and writes one four-byte output per element. Ignoring other traffic, one addition per 12 bytes gives 1/12 FLOP per byte.
Where the term can mislead
An intensity calculated from source requests cannot be paired blindly with a measured DRAM bandwidth. Caches can change the byte count.
Connect the idea
Take it into practice
Continue with the existing concept, apply it to an interview problem, or follow a course lesson. Access requirements are shown before you open a page.
New to GPUs? Start with the free execution-model concept.
Sources and scope
Examples here are teaching calculations, not measured GPU performance. Consult the linked documentation for the exact device, instruction and tool version. Source review: 25 October 2026.