Just curious, what is the FPS Dolphin reports when you play your games. On average, for example, what's your FPS in Tales of Symphonia and Wind Waker. Dolphin also displays a % at the bottom of the screen (run Dolphin in Windowed mode, you can't see it in Fullscreen); what's the average % you get for these two games?
You could try running other versions of Dolphin as well. 3.5 is no longer supported, but this could reveal if it's something to do with Dolphin or if it's your hardware. Just so you know, your specs should do phenomenally well in Dolphin; it's completely odd that you're getting these kinds of slowdowns.
This is perhaps the most drastic option mentioned so far, but sometimes people find a clean Windows install does the trick, for various underlying reasons I'm sure. I can't recommend this until you've exhausted every other end, but it has worked in the past for some people. We can't pick apart their PCs to find out if it was some other software interfering with Dolphin or something to that effect, so it's not like we ever find the root cause of issues solved by reinstalls, that is to say there's still no guarantee it would work in your case, hence it's a drastic option. Still an option to keep in mind if all else fails.
You could try running other versions of Dolphin as well. 3.5 is no longer supported, but this could reveal if it's something to do with Dolphin or if it's your hardware. Just so you know, your specs should do phenomenally well in Dolphin; it's completely odd that you're getting these kinds of slowdowns.
This is perhaps the most drastic option mentioned so far, but sometimes people find a clean Windows install does the trick, for various underlying reasons I'm sure. I can't recommend this until you've exhausted every other end, but it has worked in the past for some people. We can't pick apart their PCs to find out if it was some other software interfering with Dolphin or something to that effect, so it's not like we ever find the root cause of issues solved by reinstalls, that is to say there's still no guarantee it would work in your case, hence it's a drastic option. Still an option to keep in mind if all else fails.