I have not made any upgrades to my 17in early 2011 mbp yet, although I have asked questions about it on these boards in the past and people are always super helpful. I am getting closer to spending some money and I am just curious about one of my main slowdown issues: My wife and I share the laptop which is hooked up to a 27in Thunderbolt display. Switching between users takes forever (being a little dramatic, but about 2 min to switch over) and then it lags for a good 2 to 3 min. After that 2 to 3 min, everything seems to operate at a normal speed. Would my 5400 rpm stock hard drive be the prime bottleneck, or my stock 4gb of ram? Thanks again to the macrumors community.