Another mysterious crash. We run for three weeks or so continuously, no power off, then suddenly it dies. This time I thought to start from system rescue disk and try memory checks. This did seem to produce reporducible dying. After three crashes in a row I decided to bit the bullet and replace the innards. Yes, it would be possible just to replace the memory and see if that helped, but its productive time being lost at every iteration of this problem.
The result is surprising. Now I have 16G memory in two sticks, and an i5 processor in an Asus itx board. It is a lot quieter and a lot cooler than the previous rig. In fact you can just about hear it. Started from the old hard drive with no problem and everything runs perfectly though rather faster.
So, if you are looking for a compact and fast configuration, get the Silverstone mini itx case with the big fan on the front, put an i5 in it, and its perfect for a compact desktop. Recommended. I liked it with an i3, but this is superb.
Al