Getting some sort of errors with 'very good', "Production" and "Ultra" renders

I'm sure I typed in a long message and it hasn't appeared on the forum

I'm having problems with SR - test renders were quick and easy and nice and fast, but I'm trying to find a production render setting (to compare to how long they take with SR compared to when I choose the settings myself) and I'm not getting to the end of any testing......

I tried my favourite IM/LC at Good, Very Good, Production and Ultra.

None of them would finish.

The attached file was over 2hours and got stuck at the last 2 buckets, yet I know my computer isn't busy rendering because it becomes very usuable (i.e. I can work on it - normally when rendering, my computer is unusable whilst it is busy).

I'm feeling a bit dejected with this right now because I feel that I've exchanged my way of working to test a new way of working..... which may or may not finish rendering.

I'm willing to accept that maybe because I'm not an expert in VRay that I need to look at a setting that SR is setting and 'fine-tune' but I feel like I've purchased a problem, not a solution.

What could be making SR hang like this in this image ??

It took my personal setting 2hours to get a very acceptable (to me) render.

Please advise.

Thanks.

Jez

Thanks Jerome I will try this.

I am on 3DS Max 2013 Design and using 1.2.1. VRay 2.40.? (3 I think).....

Windows 7 64bit.

Here is the screen grab I meant to attach