Badly Drawn Boy wrote:
To troubleshoot this, it would help to know whether the processor speed, RAM, graphics card or hard drive speed would have the biggest influence on the performance in LR.
Since LR doesn't use GPU, you can scratch off the graphics card as long as it's got enough juice to render the screen. Then in terms of CPU speed, CPU cores, ram and drive speed, the anser is, yes, all of the above. The problem is, some things are more important than others depending on the function or task you are doing. For example, importing is disk bound as is fetching rendered previews. So things like scrolling in Library to zooming into Loupe or Compare or Survey will be faster if your HDs are really fast.
Doing image adjustments in Develop are more of a CPU speed and core count issue. Multiple cores are better, and the more the better up to a point. Obviously, faster CPUs will be faster too. When you fist load an image in Develop, LR rips a full size raw preview and doesn't use the rendered Library previews. So, HD speed is a factor there. The size of the display (a 30" requires a lot more rendered pixels than a 24") has an impact...this is again CPU speed and core count related.
Export and Edit in Photoshop are a combination of HD and CPU...faster/more is better.
As for ram, as long as you have enough, more ram won't make LR any faster. How much is enough? That depends on your OS, the raw file sizes you use and what sort of stuff you are doing and how many other application you are running. It's really tough to give an ideal, but if you look at your activity monitor in Mac or the Win version and you never see the free ram fall below a1 Gig, you're prolly fine. If you see spinning beachballs, the odds are you don't have enough ram.