If the programs you're don't even use 6 GB, effectively you have just added 6 GB of unused RAM. That's great. It proves that you (like most people) don't need more than 8 for your job mix. In fact, I doubt if going back to 4 would have a noticeable effect.
Replacing the CPU (if that's possible with your motherboard) is a better idea. But quite often you also need a new motherboard and new RAM for that new CPU and, well, that amounts to a practically new PC. But you can keep your SSD and HD.
Kees
I'm runnning Win 7 Pro 64bit on an ADM A6 -5400K with Radeon HD 3.6G and got 12G of installed RAM. I also got a 60G SSD where all OS files are installed and got a second drive where all applications are being installed. I recently added an upgrade to my RAM and increased it to 12G (was 6) however i have not seen much increase in performance. To be more precise i often notice in task manager the CPU graph to limit up while memory remains under 50% (~4G of use). I had disabled pagefile but with not much success and now re-enabled it. Is there any suggestion from you in order to take advantage more of my new memory or i should definately replace my CPU?
PS Its my work PC, mainly run Office Apps, no games

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