The i5-4670 does not have turbo boosting enabled by default.
The i5-4670 does not have turbo boosting enabled by default.
Your power and current restrictions seem fixed in the BIOS. Some 4th Gen Haswell processors include a PowerCut function. It manipulates the CPU to display lower power usage, allowing it to operate at full speed without being limited by power or current caps. To test this, open the FIVR window when your PC is idle and adjust the VCCIN voltage to a specific value—like 1.7998V for your model. Press Apply. Then verify the PowerCut setting and try again. Afterward, perform a stress test to observe any changes. Your screenshot indicates Locked next to PowerCut, suggesting it may not function as expected. With BIOS-imposed limits in place, other adjustments are unlikely to succeed. The default turbo ratios (38, 38, 37, 36) might also be misconfigured by the BIOS.
EDP Current reduction typically happens when the BIOS adjusts a CPU current limit too low. This is generally unrelated to your power source.
Likely a Windows problem. After installing macOS, I enabled the full core load mode in Intel Power Gadget. The outcomes match what I saw in Linux.