You have a GPU solution to speed up Photoshop and Lightroom? How about PDF rendering?
I know an AC has already addressed these points, but I feel like addressing them again, and I have time.
Not only is at least Photoshop already GPU-accelerated, but PDF rendering is also 2d-accelerated. Things like drawing lines have been accelerated by video cards Since Windows 3.1 or thereabouts. That's when the first consumer-level PC 2d accelerators started to come out, from names like ATI and Radius. They had bigger, more special video drivers than did earlier video cards, because they performed 2d acceleration of things like drawing primitives and even text. By the end of the Windows 3.1 era, 2d-accelerated video cards were the norm rather than the exception, and $40 Trident ISA cards had acceleration, not just $200 Radius cards.
You may also not remember when Macs got Color Quickdraw, in the Macintosh II era. The Macintosh had always been sort of an odd fish in that it was a graphics-only OS designed for a system with no graphics acceleration whatsoever. It had a dumb framebuffer, and clever software routines for drawing primitives. This situation persisted until the Macintosh II series, when Apple brought out the 8*24 GC, not to be confused with the 8*24 which was non-accelerated. I believe the 8*24 was around $200 and the 8*24 GC was about $500. I only mention this because it was going on around the same time.
Video cards even used to be designed to accelerated Autocad for DOS, and had special drivers for this purpose.