A synthetic noise function is a key component of most computer graphics rendering systems. This pseudo-random noise function is used to create a wide variety of natural looking textures that are applied to objects in the scene. To be useful, the generated noise should be repeatable while exhibiting no discernible periodicity, anisotropy, or aliasing. However, noise with these qualities is computationally expensive and results in a signicant fraction of the run time for scenes with rich visual complexity. We propose modications to the standard algorithm for computing synthetic noise that improve the visual quality of the noise, and a parallel hardware implementation of this improved noise function that allows the use of reduced precision arithmetic during the noise computation. The result is a special-purpose function unit for producing synthetic noise that computes high-quality noise values approximately two orders of manitude faster than software techniques. The circuit, using a commercial CMOS cell library in a 65nm process, would run at 1GHz and consume 325um x 325um of chip area.