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# supportsVertexAmplificationCount(_:)

Returns a Boolean value that indicates whether the GPU supports an amplification factor.

```
func supportsVertexAmplificationCount(_ count: Int) -> Bool
```

## Parameters

`count`

An integer that represents the number of output streams you want the GPU to generate from an input stream.

## Discussion

A vertex amplification factor of `1` has no effect because it effectively disables vertex amplification.

> Important:
> Passing a vertex amplification factor of `1` or less to this method triggers an API validation error.

For more information about vertex amplification, see [Improving rendering performance with vertex amplification](/documentation/Metal/improving-rendering-performance-with-vertex-amplification).

---

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