# Transfer cost

The time spent moving data between machines, or between host and GPU memory. Often the reason an operation is not worth accelerating.

Source: https://university.eugo.io/glossary/transfer-cost

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The reason a GPU can measure slower than a CPU on small work: the data has to get there and back. Worth checking whenever an operation that should be faster is not.

## Related terms

- [GPU offloading](https://university.eugo.io/glossary/gpu-offloading) — Moving computationally intensive operations onto a GPU. Eugo applies this automatically when a GPU is available and the data transfer is worth its cost.
- [Serialization](https://university.eugo.io/glossary/serialization) — Converting Python objects into bytes so they can be sent to another machine. Large task arguments are serialized and copied to every worker that needs them.