Thinking about the great Ansel Adams, who viewed what we now call post processing then called the darkroom as a very significant portion of his process, I think he'd be both thrilled and thinking about how he could extend his worl with it.
I'll echo the comment about checking what your current power supply will support. Off the rack PC systems in past years typically had power supplies in the 250-300 watt range -- newer, more powerful graphics cards require substantially more, usually 400-500 watts or more.
Old movie line: "I'm ready for my close-up..."
Always a Buddy Rich fan -- but a very disappointing memory! Late '60s our high school stage band (for which Buddy was an icon) made special arrangements (and worked to get parental support) to see him play at a club in Rochester, NY. The bummer for the night: right after the first set finished, local police put him in handcuffs and marched him off stage for marijuana possession. Never did find out where the bust originated but the good news is after a delay they did let him back on for the final set. Guess we can now say times really have changed. A really late (school) night but memorable for both the music and the "incident."