computer graphics is doing a lot of very small (4x4 matrices) linear algebra GPGPU is often about doing few (or one) very big (10^9 x 10^9) matrix op. You can

computer graphics is doing a lot of very small (4x4 matrices) linear algebra GPGPU is often about doing few (or one) very big (10^9 x 10^9) matrix op. You can split big matrix op into smaller ones, but with a big matrix you need to combine the results; with independent smaller matrices you don't.