Using FFT to dot matmul is much more memory intensive, IIRC. CUDNN supports FFT to do matmul as well as convolution/correlation and can also be configured to a

Using FFT to dot matmul is much more memory intensive, IIRC. CUDNN supports FFT to do matmul as well as convolution/correlation and can also be configured to automatically use the best algorithm. In some cases the FFT method has the incidental side-benefit of data reuse, like in the case of FIR filters, where the data allows for partitioned convolution.