Nik Effects Plug In Unacceptably Slow

Hi guys,

I am running Aperture 3.3.2 on a 2011 27" iMac, 2.7GHz i5, AMD Radeon HD 6770M GPU (512MB RAM), 12GB RAM, 1TB spinning hard drive.

Running OSX Mountain Lion.

I am using a variety of Nik Effects plug-ins to edit photos taken on a Cannon 5D MkIII.

The plug in I am using the most is Colour Effects Pro 4 and I am finding that the time taken to make even small adjustments is unacceptably slow.

For example adjusting the Highlights or Shadows sliders in the Tonal Contrast Filter can sometimes take 4-5 minutes to complete.

It doesn't seem to be a RAM issue as the issue can happen even when there is plenty of RAM available.

By comparison, running Aperture and Colour effects on my 2011 Macbook Air (less RAM, slower CPU, SSD) I see very minimal lag when making adjustments.

Any advice would be most appreciated as this is completely killing my workflow.

Thanks all...

SBR