More information would help. Off the top if your computer is new or if you have added lots of data the indexing could be running. Make sure defrag isn't running, be sure defender isn't doing a disk scan.
Computer Type PC/Desktop System Manufacturer/Model Number Custom OS Windows 8.1 x64 CPU Intel Core i7 4790K @ 4.5GHz Motherboard Asus Maximus Hero VII Memory 32GB DDR3 Graphics Card Nvidia GeForce GTX970 Sound Card Realtek HD Audio
PSU Corsair AX760i Case Fractal Design Define R4 Cooling Noctua NH-D15 Hard Drives 1x Samsung 250GB SSD
4x WD RE 2TB (RAIDZ)
Computer Type PC/Desktop System Manufacturer/Model Number Custom OS Windows 8.1 Professional 64-bit CPU Intel Core i5-3570k Motherboard ASRock Intel Z77 Extreme4 Memory 8GB Graphics Card NVIDIA GeForce GTX 670 Screen Resolution 1920 x 1080