A modern graphics card and CPU already boost as high as their heat and power limits allow. Give them less voltage for the same clock and they run cooler, quieter, and hold that clock for longer. An overclock does the opposite: more heat and more voltage for frames you cannot see. The tune never touches voltage; this is how you do it yourself, and the tune's report says which parts apply to your PC.
Twenty minutes, with MSI Afterburner (free). Every step is undone by the reset button.
Play a demanding game for ten minutes with Afterburner's overlay or graph open. Note the core clock the card settles at under load.
In Afterburner press Ctrl+F. Each point is a voltage and the clock the card runs at that voltage.
Take a point around 0.90 V on a 30 or 40 series card (0.95 V on older ones). Drag it up to the clock from step 1. Select every point to its right and pull them level with it (hold Shift and drag, then press L on the point to lock it on newer versions). Apply.
Twenty minutes of the heaviest game you play. A crash, a driver reset or artefacts mean that clock needs more voltage: drop the point by a step and test again. Save it as a profile and tick "apply at startup".
AMD Software › Performance › Tuning › Custom, turn on GPU Tuning and Advanced Control. Lower the voltage in small steps, twenty minutes of a game each, and stop one step above the first crash. On RDNA 3 and 4 cards the power-limit slider can also go to its maximum without adding voltage.
Intel Graphics Software › Performance: a small voltage offset is where Arc gains, tested the same way. The frame limiter is in the same panel.
BIOS › Precision Boost Overdrive › Curve Optimizer › All Cores, Negative. Start at 15 and go further in steps of 5 while it stays stable; every chip is different. An hour of a game and a stress test after each change; any crash, reboot or odd error means one step back. Lower temperature, higher sustained boost.
Install the newest BIOS for your board before anything else: it carries the microcode that stops these chips degrading. Then leave the voltage to the board's default profile unless it offers a negative offset; a small one is the same idea as Curve Optimizer.
With a variable-refresh monitor (G-Sync or FreeSync), cap the frame rate a little under the refresh rate so it never leaves the range the monitor smooths.
NVIDIA app or Control Panel › Manage 3D settings › Max Frame Rate: three below the refresh rate. G-Sync on, V-Sync on in the driver and off in the game.
AMD Software › Gaming › Radeon Chill on, with the minimum and maximum both three below the refresh rate, and FreeSync on.
More voltage and more heat for frames you cannot see, and the first thing a crash points at.
Apply at startup only after it has survived a real session. An unstable profile at boot is a harder fix.
Many laptops lock the curve; the maker's own performance mode is the safer lever there.
Power plan, services, network, game files, and a BIOS checklist for your board; never voltage. What the tune does.