Disclosed is a method and apparatus for testing devices that will be connected to a computer storage media device by generating a complex test waveform that emulates operation of the computer storage media device using at least one Graphics Processing Unit (GPU) and applying the generated complex test waveform to the device(s) being tested. The complex test waveform may be generated by calculating a plurality of discrete individual portions of the complex test waveform in parallel, in real-time, and continuously using the parallel processing features of the GPU(s). The discrete individual portions of the complex test waveform may be representative of various characteristics of the emulated computer storage media device operation such as operational characteristics of the computer storage media device, environmental effects on the computer storage media device, application of filters to the computer storage media device signal, etc. Various embodiments may generate the base data signal waveform from the emulated computer storage device such that the entire complex test waveform is calculated. Other embodiments may use a pre-existing base data signal waveform provided from another source and modify/alter the pre-existing base data signal waveform to generate the complex test waveform. When available, one or more Central Processing Units (CPUs) and/or CPU cores may also perform calculations in parallel with the calculations performed by the GPU(s).