The HEVC video coding standard requires nearly 70 % more time than H.264/AVC to encode a video sequence. Manycore architectures can considerably help to reduce the coding time. In this paper, we propose the use of GPUs to perform the intra-picture prediction without any R/D loss. We have evaluated our proposal and compared the results with the ones obtained when running on a CPU. The results show that a time reduction of up to 85 % can be obtained without any R/D loss.