Emulator

Game Name?
F Zero GX

Game ID?
GFZE01

What's the problem? Describe what went wrong in few words.
Enabling Dual Core causes framerate to drop to abou 20-30pfs

What did you expect to happen instead?
For the game to run at 60fps

What steps will reproduce the problem?

1.Load Game with Dual Core Enabled.
2.Enter racer selection screen.
3.Watch framerate drop to 20

Dolphin 3.5 and 3.5-367 are old versions of Dolphin that have
known issues and bugs, so don't report issues about them and test the
latest Dolphin version first.
Which versions of Dolphin did you test on?

Does using an older version of Dolphin solve your issue? If yes, which
versions of Dolphin used to work?
4.0.2
4.0-4971
4.0-5064

What are your PC specifications? (including, but not limited to: Operating
System, CPU and GPU)
AMD FX6300 @ 3.8GHz
MSI Radeon HD 7870
Windows 7

Is there any other relevant information? (e.g. logs, screenshots,
configuration files)
Frame rate drops only during character selection screen and in race. 60FPS everywhere else.
Was using 4.0-4971 a few days ago and was running with dual core enabled. I was getting 60fps everywhere.