With dolphin it's all about the processor. The above post says it well.
As for a graphics card, you may want to consider integrated graphics until you save up a bit more money, and really raise the processor budget in turn...maybe even that 4670k: The Intel 4600 integrated may not play modern pc games, but i'd wager it has no problem with dolphin @ 1.5X or even 2X native resolution (fine for 720P) based on what i have seen. The jump from 1X to 1.5X is actually huge imo.
By doing so you would get better emulator performance (less cpu bottleneck) while still having the capacity for adding a good graphics card and aftermarket cooling in the future.
As for a graphics card, you may want to consider integrated graphics until you save up a bit more money, and really raise the processor budget in turn...maybe even that 4670k: The Intel 4600 integrated may not play modern pc games, but i'd wager it has no problem with dolphin @ 1.5X or even 2X native resolution (fine for 720P) based on what i have seen. The jump from 1X to 1.5X is actually huge imo.
By doing so you would get better emulator performance (less cpu bottleneck) while still having the capacity for adding a good graphics card and aftermarket cooling in the future.