You're paying a lot for a 7800x3d, and putting in a 7900 GRE which won't come close to saturating that CPU. You'd end up with more FPS if you saved $200 on the CPU and put into the GPU for an XT or XTX if you can squeeze it.

Also, if you can hold off on purchasing, the 9000 series CPUs go on sale at the end of the month. If you wait a couple months you can probably either pick up a used CPU from someone upgrading, or the existing new prices should drop a bit as demand shifts to the new higher level.

In general though I'd say "more money into your GPU" if gaming is your primary goal. My friends and I are generally sticking with the "video card price = CPU + mobo + RAM price" as far as high performance gaming rigs go at the moment (and even higher if you're doing Nvidia because they're overpriced.)