Intel Core i5-8600K is processor manufactured by Intel and launched in Q4 2017 . It's using FCLGA1151-2 socket. It has 6 cores and 6 threads with clock of 3.6 GHz that can turbo clock itself to 4.3 GHz . This processor is used in Desktop devices and can consume up to 95 watts of power .
NVIDIA GeForce GTX Titan is graphic card manufactured by NVIDIA and launched in Q1 2013 . It's using PCIe 3.0 x16 bus type. It has core clock of 837 MHz and 6144 MB (6GB) of memory . It supports DirectX 11 and OpenGL 4.5 . This graphic card is used in Desktop devices and can consume up to 250 watts of power .
This configuration has 0.4% of processor bottleneck . Everything less than 5% should not be concerned major bottleneck.
Processor bottleneck is worse, than graphic card bottleneck, because utilization of your processor will be on maximum and it will throttle other programs that are ran in background. Also you won't experience maximal performances that your graphic card offers.
You can resolve this by upgrading your processor or by downgrading your graphic card. Downgrading your graphic card doesn't make much sense and in that case is better to leave current graphic card in you computer.