V9.7 Framerate Issue

[Hampster]

Hi all,

 

This issue has been slightly putting me off X-Plane lately because it persistently won't go away.

 

I'm running V9.7 on a 27" iMac, specs:

 

processor: 3.6 GHz Intel Core i5

memory: 12 GB 1333 MHz DDR3

graphics: ATI Radeon HD 5670 512 MB

OSX.9.5

 

Problem:

The frame rate in the sim seems to crash right down to 19fps with even basic rendering settings. When I got the Mac a few months ago, I could run V9 with no frame rate issues with the rendering settings set to 'totally insane'. Now even developing basic planemaker models, I can not do this without the sim jolting and drawing in the annoying volumetric fog, even when I take the fog setting off. I can only get 24fps out of V9 when everything is set to its lowest rendering setting. As soon as I turn on pixel shaders or increase texture resolution, the frame rate will crash down to 19. PlaneMaker is even having issues and is going all juttery.

X-Plane is telling me it is using about 170 MB of VRAM, and my mac is telling me that it has 512 to give, so what is going on? It should be smooth, shouldn't it?

 

Even on my old slow mac, I kept things running well for five years. I've never seen this issue before...

 

I hope I can resolve this issue...

 

Thanks,

 

Hamish