You don’t need to buy a PC to play VR games with Oculus Rift and HTC Vive. NVIDIA GeForce GTX 10-series graphics cards will be inside laptops to handle the job. The GTX 1060, GTX 1070, and GTX 1080 are almost identical to their desktop counterparts. The GTX 1080 runs 2,560 CUDA cores at 1733Mhz, with 8GB of GDDR5X memory.
Plenty of PC makers are expected to offer these cards in their new laptops (XOTIC PC is already doing it). More information is available here.