I'm looking for some comments and input on why LR 4 is running so slowly for me. I have my theories, but I absolutely will not spend money on hardware upgrades until I figure out which hardware upgrades will help me the most.

Here's what's going on. I'm running a 2010 Macbook Pro 13" with a 2.4GHz Core 2 Duo processor, 4GB RAM (stock) and a 250GB, 5400 rpm HDD. The internal hard drive usually has around 30GB free at any given time. I shoot entirely RAW. Now, how I work is I create a catalog on my local drive, work on a shoot there and then offload (import) it into my master catalog of just under a hundred thousand photos. This master catalog, its preview and all digital negatives live on the same 640GB, 5400 rpm external drive, which is connected via USB 2.

Having been shooting a lot lately, it is driving me up the wall how slow LR is running once I go from a small catalog on the local drive to the master catalog on the external. Though editing works fine, grid view is deathly slow, often too slow to work productively (I work through old stuff all the time). This got me to thinking that it's got to be one of three things: the USB 2 connection, the 5400 rpm drive or the computer itself. After looking online at the options pertaining to these three potential bottlenecks, I decided to try an experiment. I copied my 1.24GB catalog file to the local drive in the computer. Once I opened it, it was more than usable as far as speed is concerned. SUBSTANTIALLY faster. Does this automatically mean USB 2 is my biggest bottleneck? Oh and I did perform an optimization, which further improved performance by a small margin. I don't know if grid view could get any zippier. Granted, only a few dozen preview are rendered (I don't want to copy my 100GB previews file right now, no space locally), but this thing sure is fast.

This brings me to my next point: upgrades. Up until now I was planning on going with an external 7200 rpm drive for photos + catalog + previews, but now I'm thinking it will be external HDD for photos only, while the catalog and preview will reside solely on a 128GB Crucial M4 SSD. I feel that this alone would make things even faster if I were to utilize my FW800 conneciton on the laptop. But would it? Or would having things on the internal drive be the fastest of all? Secondly, I will be upgrading to a more recent laptop sometime in the near future. I would really LOVE to go with the conveniently small 11" Macbook Air, and I'm more than certain that the new models will outperform my current system by a long shot. Either way, I could either host the catalog and preview on an external SSD connected via USB3 or internally, and the photos themselves will reside on an external 7200 rpm HDD connected via USB3.

Comments, tips and suggestions GREATLY apprecaited!