So I am a Lightroom user and I plan to be a future 5D Mark II user as well. I have been worried that the move from 8 megapixels to 21 megapixels would be too much for my computer to handle. So I started to investigate what my options were to ensure I could continue to working on my shots quickly for a long time to come.
Ok, so my main computer now is a 13 inch macbook that I got in the spring of 2008. While this had initially been working fine for Lightroom, it had started to become sluggish and I knew that if things didn't change then I would never be able to work with larger RAW files. So what were my options?
So first I want to take a second to discuss some of the factors that affect the performance of Lightroom and why.
Hard Drive Hard drives can affect performance some and it has to do with how fast Lightroom can get access to your files. A drive with a faster spin rate will read/write images faster and Solid State Drives (SSD) can also improve that read/write speed.
This is typically a factor in slow Lightroom when a drive is close to full because finding space to write content is harder to do with a full drive.
Processor
The processor can play a huge difference when working with RAW files. This is because your computer has to work hard to take that sensor data and turn it into output for your monitor. The larger the RAW file size, the more work the processor has to do. The faster your processor is, the less time that it will take to do that work.
The processor also come into play a lot when you are using the develop module since your computer has to apply a lot of changes to an images for those development changes to show up.
Memory (RAM)
I mention a fast hard drive will help speed up Lightroom but you're going to get nowhere near the speed that your memory will give you. The problem is that when you run out of RAM, your computer has to start using the hard drive to save that information. So, the more memory you have, the more you can do before you have to move to the big/slow/ugly hard drive.
replacing the memory in a mac
So, what did I do?
Well, I could upgrade to a newer computer with more power. While that could improve all the pieces, it was also the most expensive. I was looking at $1000 to get a high performance laptop. Before biting that bullet thought I would see what else I could change to increase performance.
The hard drive wasn't full and was fairly fast. Plus It would take a full reinstall to make that upgrade and would probably cost a few hundred to get. That was just more work than I wanted to do.
The memory, now that seemed like a great place to start. I could improve my 1GB of memory and increase it to 4GB for only $50 from Crucial and Amazon. That seemed like a no brainer to me and it would literally only take 4 minutes to make the change.
finding out how much ram your mac has
The Results
Let me just say that upgrading the RAM by 3GB made a world of difference. Now I can run Lightroom and Word and Firefox and not see any slowdown.
If you have any slowness and you have room for more RAM then I would suggest starting there to improve performance. And the boost will not only improve Lightroom but will improve system performance overall.
user and I plan to be a future 
user as well. I have been worried that the move from 8 megapixels to 21 megapixels would be too much for my computer to handle. So I started to investigate what my options were to ensure I could continue to working on my shots quickly for a long time to come.
that I got in the spring of 2008. While this had initially been working fine for 
