Oh, your about to get lots of opinions
So, first up
1. First up, lots of RAM, think beyond 16MB
2. Internal hard drives, lots of separate drives. Your boot drive can be old fashioned non solid state (I am thinking about total drive space old style vs SSD). Naturally all programs, and the OS go their. Your LR catalogs do not.
2b. Separate SSD for your catalog, it works quicker if (a) not on the boot drive with all that clutter, and (b) on a nice quick SSD.
2c. Separate SSD for your Camera Raw Cache, and for other CACHE and paging files, they all work better away from the boot drive and all better on SSD.
2d. Some might even place the RAW files on a drive other than where the catalog is placed. Not sure on that.
2e. Biggest, nastiest external hard drives that will connect to the new PC. Think multiple, for multiple copies of catalog(s) and Images, Think one to keep attached, one to lock away hidden somewhere in case of theft. And consider placing images on one. (apparently working with smart previews works nicely if you can divorce the external hard drive with images from LR). NOTE, for your LR backup, I recommend actually think of your LR catalog copy, and if you keep the images in the same folder/drive, the entire folder, Using LR to Backup typically just copies a zipped up copy of the catalog not the images, so you may need more space than you think to really backup everything.
2f. Do you have a laptop/MacBook for work when on travel? If it is an apple product, consider the ports on at least one external hard drive. In my case Firewire is needed along with a USB port to use best on both MAC and PC, and if you have a external HD for this hybrid situation, partition it on the MAC as eXFat.
3. Water cooling instead of air cooling
4. latest biggest, nastiest GPU.And make sure you buy it with max RAM, near impossible to buy that particular RAM later. Do not go cheap on the GPU. Something in the Navida line????
If someone boo poos GPU in LR, do not forget your PS as well, and any other GPU intensive apps you ma=y have, and any future LR changes that start to really call out for GPU.
One lesson learned from my last build. those newer CPU's are getting thinner and thinner, easier to damage, so take extra caution. And immediately upon build finish update that BIOS.
Incidentally, non LR, include an internal hard drive in your misx just for files, your spreadsheets, your word processing, your downloads, your well everything that is not an actual running program, and not a LR catalog, or a image, or a CACHE. keep then on a separate hard drive, easier to back it up often, than those plus everything on the boot drive.
Appreciate the response. I understand part of your response, bur you're bouncing around a little. You suddenly introduce water cooling? Why?
Lightroom can, especially when things go wrong put a stress on the CPU, Water cooling can keep the CPU cooler with less noise. Incidentally, if you are into gaming and plan on overclocking the MB, and GPU, then water cooling enters in big time, including the GPU. If you are not going to overclock, and you do not mind some extra noise, then air cooling is Ok
Mostly RAM RAM RAM, and hard drives
Definitely no games! How much RAM? 32GB enough? What's the best processor available today for browsing and working in the Develop module.
Get the fastest CPU you can afford. Most of the develop module operations depend on CPU speed (and GPU speed, if enabled), and any slowness you get there can be improved by a faster CPU.
16GB is enough for LR. The only operations in LR where 16GB might be a limitation is panorama and HDR. Anything more than 16GB is wasted on LR (but might be helpful for other software).
You want an SSD for your catalog. The photos can go on an ordinary external HD. The speed of your drives does not affect the develop module at all (other than a trivial amount that you will not notice). Please read Ian Lyons' paper on this: Will an SSD Improve Adobe Lightroom Performance? | Computer Darkroom Although this paper is about 3.5 years old, Mr. Lyons recently stated that his conclusions have not changed since then given his continued testing.
The Develop Module seems to have several causes of slowness. One is a 4K or larger monitor. This can be overcome with a proper graphics card, any new card will do the job. The next cause of slowness is doing a lot of local adjustments, either brushing or spot healing. The use of the graphics acceleration by the GPU makes this worse. In my opinion, if you are going to do a lot of brushing and/or spot healing, do NOT get a 4K or larger monitor. Stick with a 1920x1080 monitor.
If you are getting a desktop, I wouldn't worry about water cooling, as the cases are designed to have fans and air flow and generally heat build-up is not a concern for desktop computers (unless some element of the cooling system fails). It is a concern for some laptop computers, but as far as I know, there is no such thing as water cooling in a laptop.
I've posted on several sites and this is the BEST reply of the bunch. Thanks a lot.