CPU maxing out when setting up materials

Hi,

I've been experimenting with LumenRT, but I've just gone back to basics and started to familiarize myself with modelling in microstation.

I've got a new computer and I'm finding i'm having issues when flicking through settings in the materials editor, the CPU is maxing out and bringing my computer to a complete halt when I simply adjust the settings (such as scale of the pattern, diffuse setting, or colour setting).

I have a few models (trees) that are complex, but I've switched them over to fast cells whilst working in the drawing. I've swiched off layers, it just stops and starts with every move.

I'm using V8i 08.11.09.829, haven't made the switch to Connect - we've got some other software developed only for V8i.

I'm curious if my memory settings are wrong also. See below.

I tried to attached the file I'm working in but it's too large apparently @ 50meg.

Appreciate your thoughts,

Nicola