How much or how little to spend?
1. Check for page outs in activity monitor. If there's not much there, you don't need ram (even though it's the best bang for the buck upgrade there is IF YOU NEED IT).
2. The big culprit could be her older 5400 rpm hard drive filling up.
a. Is there old crap (copies of unused os'es, unwatched movies, old tv shows, pictures of ex-boyfriends and dead pets) to delete and make space?
b. Bigger or faster conventional hd. Just swapping out an older filled up hd for a newer and bigger one can help a lot. 7200 rpm hard drive can result in noticeably improved boot and app load times.
c. Hybrid hard drive? Assuming what you learned through your research was valid, and the larger, more capable momentus xt won't work, I see this as being the least effective bang for the buck. Considering a hybrid has less capacity and is the same price or more than a larger conventional 7200 rpm drive, you'll only gain slightly improved boot up and app launch times.
d. The robvas solution. SSD's are probably the best way to give an older mac that fresh from the apple store smell and feel back. The WD blue is a good, solid, dependable drive and has less power usage and vibration than most for mass storage. It has the best of both worlds and can fit into her little portable.
3. Other considerations.
a. Law of diminishing returns. Depending on which of the options you choose, the cost can be from nothing to possibly up to $500 for maxing out the ram, an SSD, the 2nd hard drive and the optibay. More money spent now means less money to spend later for a newer, more capable system. Let's say you can buy her another year of comforable use with a ram upgrade and cleaning non essentials off of her old disk. 512 gb ssd's that are now selling for $400ish now will probably be selling for $300ish or less in 2013. Wham, bam, thank you (says) ma'am!
b. Congratulations, you'll now be her personal apple genius! If anything goes wrong with the install, you will be held responsible. And if anything breaks down the road, it will be your problem solely. With a stock system, she can take it to the apple store, let the pros mess with it, and you can stay at home and catch a game. Win/win!
c. What does SHE want? Let's say you're in a committed relationship, and co-habitating. Proudly, you present her old laptop, she notices a difference in how it operates and asks you about the cost. God help you if you tell her that it only cost $435 of 'our' money if you didn't go over that with her first. You will then learn that she'd rather burn the old pictures and movies to DVD's and have the mother of all spa days (or shoes, fancy dinners, whatever) with the remainder. And the aftermath will not be pretty.
d. Use case scenario. If it primarily sits at a desk plugged in, couldn't you sell the mini pro and buy a baby iMac? Make damn sure you discuss that option over with her before exercising it, or you will have the rich social life of a benedictine monk for the foreseeable future.
Just some things to ponder. Good luck!
