Try checking only the Online Symbols box and putting into the Online Symbols text box your usual symbols path you use for WinDbg. See if the app runs faster with that option.
It's a workaround to an issue I believe originated from accessing Microsoft's symbols cache on their server. Something slowed down significantly with server symbols a few months ago. I'm not sure whether it's an issue with the app, the server, or the kernel debugger accessing the server.
I'm having the same issue. + on every dump I get the message: *** ERROR: Module load completed but symbols could not be loaded for <driver.sys>.
I'd appreciated any assistance. Using latest version.