CPU or graphics card for better sculpt performance?? Or both??

For most of the stuff that I do I don't experience any problems, but sometimes I need to go over the 10 million face count and Blender starts to lag. Which is more important for sculpt performance: CPU or the graphics card?? Or both??

Here are my specs:

Processor: AMD Ryzen 7 1700 8 Core MultiThreaded 3.00 GHz (16 virtual cores)
RAM: 32 GB
Card: NVIDIA GeForce GTX 1080 Ti