My current computer is sort of adequate running LR 4.1, but that is all.  My computer is 2.5 years old so I have been planning to get a new one anyway, but I have held off because I have seen many posts  from people who have bought/built new, high spec computers and many of them have worse LR performance than I do.  So, clearly, just having a high spec computer will not necessarily mean I will be better off.  It seems I must be very careful and get just the right combination that works well with LR and it doesn't even have to be so high spec.  That's good for me.

I am currently using a Win7-64 17.3" laptop with i3-330m, 4gb, 500gb hd.  I changed to 8gb a couple of months ago, but after a month I started getting tons of blue screens so I took the new memory out and put the old back in and all is fine again.  The 8gb didn't seem to help any with LR 4.1 anyway since I didn't notice any performance difference. Even with only 4gb I have never seen total memory usage with LR and Firefox (multiple open tabs) push memory usage up past about 85% of the 4gb and usually it is more like 70%.  I am talking about at the bottom of the Task Manager window where it says, for example:

Processes: 75  CPU Usage: 6%  Physical Memory:  59%

Even if I also have PSE 9 open also it only on rare occasions for very short periods spikes up to about 95%.  I never do batch processing though.  Processing Canon 60D, Sony A700, Olympus E-M5, and Panasonic G3 raw files.

It seems a bit of a crapshoot these days with LR 4 since I see many people who have high spec systems, but some of them have terrible performance problems.  Other people get good performance.  I wish Adobe would tell us exactly which brands, model numbers, etc. we need to buy to get the good performance since sometimes I see that even rather mid spec computers sometimes get good performance and better than some of the high spec computers.  It seems there are certain mysterious combinations of components that LR likes and some combinations it doesn't like.  My 2.5 year old laptop, which these days is sort of low-mid spec, is not too bad with LR 4 -- not as bad as some of the high spec people.  I just don't want to buy something new, higher spec and then discover LR is worse with it.

I want to get another 17.3" laptop since I need something that is reasonably mobile because I live part-time in various places.  What specs do I need to make it worthwhile to make the LR experience enough better to be worth the trouble and money?  I don't need the best, high-end, especially since I have read so often that many of those computer have worse LR performance than even my old one.  i5?  AMD?  SSD or hybrid hd?

Also, does anyone know if LR works better under Win8?  Most new computers will start having Win8 on them this fall.