Just thought I would post here in case it helps anyone.
My issue was slow loading of screens using a laptop that is capable of running the game and can run nwn ee without problems.
Am using platinum edition disk. The laptop has integrated intel HD graphics.
I found an old post here which suggested running the game with the 'console' open. I tried everything else as I did not know what the console is....finally I found it and hey presto it works.
Here is the slightly odd bit - windows recently updated with a major new patch including a new security patch. This patch broke the work around and it was back to slow loading. I uninstalled the main patch and it still did not work.
Finally, I rolled the laptop back to pre update and the fix worked again, which strongly suggests the root problem is to do with security settings. The root problem is something I cannot identify.
Opening and closing the console it is a bit of a fiddle but it works.
Hope this helps someone at least.
P.S. The 'console' key is "`" which is next to or below the "1" key on most keyboards.