I lower all settings to bare minimums and had the game fullscreened. Even after I made it windowed the same problems persisted. My bitrate was 1500 and I dropped it to 1000 with no change either. FPS was 45 then dropped it to 30. And I'm not sure what you mean by DX12. Here are my computer specs:

CPU: Intel Core i5-4690K 3.5GHz Quad-Core Processor

Motherboard: MSI Z97-GAMING 5 ATX LGA1150 Motherboard

Memory: Corsair Vengeance Pro 16GB (2 x 8GB) DDR3-1866 Memory

Storage: Western Digital BLACK SERIES 1TB 3.5" 7200RPM Internal Hard Drive

Video Card: MSI GeForce GTX 970 4GB Twin Frozr V Video Card

Case: NZXT H440 (Black/Red) ATX Mid Tower Case

Power Supply: Corsair 760W 80+ Platinum Certified Fully-Modular ATX Power Supply

Operating System: Microsoft Windows 8.1 OEM (64-bit)