My guess: your CPU was using Turbo Boost before, but now it's not. Turbo Boost only activates if your laptop can handle the extra heat of running the CPU at high frequencies. Turbo Boost is probably not being enabled for whatever reason. Use CPU-Z to monitor your CPU's clocks dynamically; anything greater than 2.2GHz while playing Dolphin means Turbo Boost is working in some capacity.
You can force Turbo Boost to be on manually. Google "dolphin emu laptop peformance guide" and follow the relevant instructions (should step 2 or something like that).
You can force Turbo Boost to be on manually. Google "dolphin emu laptop peformance guide" and follow the relevant instructions (should step 2 or something like that).