Upgrading is going to be much cheaper, and it's pretty simply to install a new GPU and ram, it's probably the easiest upgrades to perform. There's tons of Youtube videos if you have any questions or concerns about it. The 560ti has the same power draw as a GTX 1060 or 1070 so it would be a really easy swap, just opening…
However in Zbrush you'll need CPU and more RAM, looks like you could nab an i7-3770 for about $100 - $150 used. That would be your only upgrade on your motherboard (socket 1155), and it wouldn't be a big improvement. I'd also suggest going with a video card upgrade, and decide how soon you want to go for a new…
I'd suggest getting something like a GTX 1060 w/ 6GB vram now (about $250 on sale right now), and upgrading the rest of your computer in the next year or so. The CPU is dated, but not really your main bottleneck in Substance Painter. The GPU is going to give you something like 400% better performance, while a new CPU is…
Should just upgrade your ram and your video card, your processor is fine. ZBrush's biggest performance bottleneck is memory, especially with the 64 bit version I would consider 12gb to be the minimum with 16+ being optimal. On top of that your card doesn't even meet the minimum VRAM requirements for substance so... I'd…