What CPU is in your X58 system? i7-920-950? If so, you can just throw in a nice Xeon X5650-X5680 etc. CPU, which are 6c/12t and cost about £20-50 and clock up to 4.0-4.4GHz+ using a reasonable cooler and you'll get a nice performance boost, 50% more cores and threads, which in terms of value for money vs. performance increase in productivity won't be beaten.
Why would you do this now, you ask? Well neither the current Intel/AMD platforms are perfect, and refinements are certainly being made with AMD and in all likelihood Ryzen '2' will be the real winner starting next year, by which time you'll have the benefit of DDR4 pricing having significantly reduced, as presently it is artificially high, and will contribute a huge cost to your budget especially if you want very specific RAM.
The same can be said about Intel, complete mess at the moment, 8700K is an very nice chip, overpriced to some extent, but very good. The issue is the chipset longevity, and the imminent arrival or the 8c/16t parts, which will make the 8700K defunct in it's current position on the next couple of months. Z390, with a 8900K or whatever it maybe called will be great, but again silly high prices for DDR4.
Buy a Xeon, wait until next May-June, pick up an X570 with Ryzen 3800X (12c/24t possible!), and 32GB DDR4 RAM, less than an X470, 2700X and 16GB DDR4 costs today.
