Jumping Framerates?

[Turninwheels4x4]

I've noticed, that when playing games (Midnight Club 3 and L.A. Remix mostly) that, depending on my luck, the game will either run normally (a few FPS dips here and there, compensated by frameskip) or it'll run in a way that If it doesn't get 60fps, it'll immediately jump down to 30. This sounds like a vsync problem, or maybe some external software is doing it, but no. Vsync is off (turning it on doesn't actually enable vsync; bug?) and the only other software that could possibly affect framerate is msi afterburner, and i've tried playing with it running in the background, and without it. I've also noticed that changing the emulated clock speed sometimes fixes this (but only at 666mhz?). Normally I wouldn't complain about stuff like this, but due to my PC being at the performance level of barely 60fps, as soon as I dip to, say, 59, it'll immediately jump to 30, causing a wierd form of stuttering.
Settings:

Code:

Backend: Vulcan Mode: Buffered Rendering Simulate block transfer effects: True Software rendering (slow): Greyed out and False Frameskipping: 4 Auto Frameskip: True Prevent FPS from exceeding 60 (speeds up GoW): False Alternative speed: 50% Postprocessing shader: Off Fullscreen: True Rendering resolution: 1:1 (1920x1080@60hz) Vsync: False Hardware Transform: True Software skinning: True Vertex Cache: True Lazy texture caching (speedup): False Retain cheanged textures (sometimes slower): False Disable slower effects: False Spline/Bezier curves quality: Greyed out; High Hardware tessellation (expirimental): True Upscale level: off Upscale type: xBRZ Deposterize: False Antisotropic filtering: off Texture filtering: Auto Screen scaling filter: Nearest Timer Hack: False Disable Stencil test: False Lower resolution for effects(reduces artifacts): off Fps counter: FPS Show debug statistics: False Audio is enabled with low latency All settings in System are defaults, except for the emulated clock speed (666mhz), the nickname of the psp (Turner), cheats are enabled (draw distance fix), and it caches the ISO in ram.

PC Specs:

Code:

CPU: i5-2400 @ 3.1ghz 4 cores, 4 threads GPU: Nvidia Geforce GT740, 2gb Vram, 1000mhz clock 10Gb of generic DDR3 RAM 120gb ssd, 1tb hdd running windows 10 Pro x64