library(gputools)
A <- matrix(rnorm(2000 * 30000), 2000, 30000)
B <- matrix(rnorm(30000 * 4000), 30000, 4000)
system.time(A %*% B) user system elapsed
86.900 0.210 8.112
system.time(gpuMatMult(A, B)) user system elapsed
7.46 4.05 11.59