Windows 7: Windows 7 performance monitor counters for Firefox

Hi all,
Please help with an issue regarding Firefox productivity in Windows 7.
I like to use lots of extensions and plug-ins for my FF (in fact, there could have been any other SW), but some time ago I started to experience high CPU and memory usage for the browser according to the Task Manager. I have an old notebook with 2Gb RAM, which seems to be not enough to use plenty of extensions, especially with other applications running. Basically, there was nothing special (eg Adobe, Apple plug-ins, Adblock, Fire Gestures etc.) but I had to disable all of them according to recommendations on Mozilla.org official site to reduce memory consumption (Safe Mode state). It helped, but now I have only a bare browser which is not appropriate for me.
My question is how can I collect performance statistics based on add-ons configuration? I tried to use Process Explorer utility, which is very beautiful and gives some average values, but I want real numbers to compare (I found no logging option available). I think that Windows Performance Monitor would be useful, but there are lots of counters, and I don't know which of them have relation to Firefox. Could you please provide with basic (or maybe extended as well) counter configuration to track and log main resources used by the browser? That is how I want to test CPU and memory utilization to find out less "harmful" extensions.
Thank you in advance!