@ Saalbhach & Thorsten,
Thank you both for your excellent replies. I will follow the paths you have given me to try.
how do you "know" your issue is RAM?
I know this because of other issues which have pointed to a lack of RAM. I currently only have 1GB, when my iMac can take up to 4GB.
are you sure it's the Material Shading that is the issue?
As Thorsten pointed out - With Material Shaders checked, I get a very dull screen, which shows most textures as the default colour unless light is directly shining on them. I also have fps of 5 - 15.
With Material Shaders un-checked my screen is bright, all textures show brightly, and my fps jumps to 55 - 60.
Give more details on your OS, hardware, specifics and of course, FG version, and then maybe we can assist.
If you bothered to read my first message you will have seen which version I am asking about. If you bothered to look at the information which is on the right hand side of my message, you will see that I am a Mac user. That also shows which version of OS X I run, and that I am 'Blessed' with an ATI Graphics card. I also know my graphics card is inbuilt to my mother board and therefore can't be updated or replaced.
You might also note that I have been on the forum for a little while. I offer help where I can, usually about modelling scenery. In fact I started using FG when it was at the Version 0.9.8 stage. I usually manage to keep my messages light, if not amusing. I have been known to blow my top at someone who has annoyed me over a great period until it becomes unbearable, but I never treat people as idiots until they have proved they are one. I don't appreciate getting messages like yours. If I thought that sort of information was required to answer my question, I would have provided it.
Unless you (emarkay) can agree to get out of the correct side of the bed on the day you write, please don't bother to answer any more of my messages. I find your manner offensive and rude.
Thanks again to Saalbhach & Thorsten.