I have a pretty old system: i5 3570k, 16GB DDR3 at 1333Mhz (ugh), Intel DZ77BH-55K mobo, Cooler Master Hyper 212 EVO Cooler. I'd like to upgrade in the next few years, but I rarely have time to game anymore so it's a low priority and consequently I'm pretty rusty on my tech knowledge. I did read several overclocking guides before I posted and unsuccessfully tried some similar BIOS settings used on similar rigs.After last week's Windows 10 update, I started getting micro freezes in low spec games like Overwatch (which I have set to the lowest settings outside of the 1440p resolution and 144Hz refresh rate). I upped the overclock in UEFI /BIOS to 4.30Ghz but noticed no difference. Every few minutes players would hang in the air for a few seconds and I'd be in a slightly different spot (or dead) from where I was before the lag.Looking at Task Manager, the game is nearly maxing my CPU at low setting, and when it freezes, it's hitting 100% CPU use. CPU-Z shows that I'm only running at stock 3.40GHz but Intel Virtual Bios is telling me that I'm at 4.30GHz.Is my overclock not registering in Windows anymore? Are there tweaks I could make in the BIOS settings that would give me some CPU overhead that I had on games that I've played fine for years? I could tell that performance took a hit after the Spectre and Meltdown patches, but something just feels off now.

My advice would be to take all overclock settings back down to stock. Then very slowly start overclocking a little at a time checking for stability before moving on to the next overclock. 

If returning your system to default clocks regains stability you were definitely overclocked.