First, please fill out your profile and include your Dolphin revision.
Please post screenshots of your settings. In particular, are you using HLE or LLE audio? What backend?
It's not likely that much can be done about the performance because your CPU is somewhat weak. Please post screens and we'll see if there's any magic that can be done there.
The newer versions have become more accurate to fix various bugs at the expense of raw performance. This means that it takes better hardware to run these newer versions (with bugfixes) at full speed. Of course, you can run an old version without these fixes at higher performance on older hardware.
Please post screenshots of your settings. In particular, are you using HLE or LLE audio? What backend?
It's not likely that much can be done about the performance because your CPU is somewhat weak. Please post screens and we'll see if there's any magic that can be done there.
The newer versions have become more accurate to fix various bugs at the expense of raw performance. This means that it takes better hardware to run these newer versions (with bugfixes) at full speed. Of course, you can run an old version without these fixes at higher performance on older hardware.