I just built a new computer with an i7-8700k, RTX 2080, 1200 watt PSU, and 16Gb of 3000 MHz ddr4 ram. A lot of games I play show consistently low GPU usage with some spikes up to the mid 90's. This can result in low frame rates and or massive stuttering. Testing rise of the tomb raider, for example, shows the problem well, with the gpu not even hitting above 80% usage at all. When testing the same game with the same settings with dx12 enabled the issue is much less pronounced but still not acceptable performance for this kind of card.