If you have one of the iMac models that was released in July 2010, you have four memory slots that can handle a maximum of 16GB total. Be sure to use for your memory. Find more info about and information about your specific 2010 iMac model. App Sliced recommends using a third-party vendor instead of buying straight from the Apple Store when you purchase memory. The memory quality from OWC and Crucial is similar or better than Apple branded RAM and you can literally save hundreds.
First, could you post the Apple site that is telling you to upgrade the RAM to 6-8 GB. If you want to upgrade your RAM, I would add another 4 GB for a total of 8 GB. Buy a 4 GB Kit. (2- 2 GB modules/dimms). A good place to get it OWC Be sure to get the right RAM for your Model iMac.
Find memory deals at.
About 'worth the effort': You can get the i7 870 for $100 if you look around and a decent 240GB SSD for about the same. Creating a fusion drive with your internal drive or installing the OS on the SSD itself would speed up the computer tremendously, the added beef of the i7 would also increase the performance quite a bit (the i7 would be about 25-30% faster than the current i5 IIRC). This would basically put the CPU to the same as in the top-level mid-2010 model (yours seem to be the late-2009). This would cost a total of $250 incl.
Cables to the SSD, the SSD itself and a CPU. Would you notice it in everyday tasks? Would it be worth the price? Only you can decide on that.
Upgrading the GPU to 2011 Specs though is a bit more expensive and I wouldn't think that is worth it ($250 or so by itself). But I do believe it is possible as I think all 27' 2009-2011 shared the same MXM-design. Time to install an SSD and the CPU? Dedicate a couple of hours and you should be set. Not much of an effort really, I opened my 2011 up a few times and it's basically only a unscrewing a few screws holding the screen in place, removing a few cables and loosening some screw to move the logic board. Not really a hard operation if you ask me.
About 'worth the effort': You can get the i7 870 for $100 if you look around and a decent 240GB SSD for about the same. Creating a fusion drive with your internal drive or installing the OS on the SSD itself would speed up the computer tremendously, the added beef of the i7 would also increase the performance quite a bit (the i7 would be about 25-30% faster than the current i5 IIRC). This would basically put the CPU to the same as in the top-level mid-2010 model (yours seem to be the late-2009). This would cost a total of $250 incl. Cables to the SSD, the SSD itself and a CPU. Would you notice it in everyday tasks? Would it be worth the price?
Only you can decide on that. Upgrading the GPU to 2011 Specs though is a bit more expensive and I wouldn't think that is worth it ($250 or so by itself). But I do believe it is possible as I think all 27' 2009-2011 shared the same MXM-design. Time to install an SSD and the CPU? Dedicate a couple of hours and you should be set. Not much of an effort really, I opened my 2011 up a few times and it's basically only a unscrewing a few screws holding the screen in place, removing a few cables and loosening some screw to move the logic board.
Not really a hard operation if you ask me.