I'm guessing the processor the 2010 MBP is pretty old by now and was wondering if it can catch up to 16GB of RAM.
In other words, for older processors is it not worth getting 16GB rather than just 8GB because it wouldn't be able to handle any more than 8GB worth of workload?
Or would you be able to have a lot more applications running on 16GB in spite of the older processors?
That's just not how it works.
Here's a quick analogy: Think of your processor as a person working at a desk, said person cannot work any faster than his/her normal workrate.
The RAM is the desk. The smaller the desk, the smaller the amount of work your person can work on at any given time.
So, if the desk is too small, that person will be sitting idle while waiting for the desk to fill back up (paging to and from the hard drive). There isn't really a downside to having too big of a desk. The person gets to pick and choose which part of the work he/she wants to work on.
So basically, having more RAM does not make your computer any faster, unless you were running out of it in the first place. If you are not running out of RAM and find your computer slow, you need to look at other bottlenecks in the system, depending on your workload. If you're gaming, it's most likely the graphics card, if you're cruching numbers (such as encoding video, editing video, CAD) then it's likely the CPU, and if you find opening and closing of apps or large files too slow, it's likely the hard drive is the culprit.