The equivalent Haswel chips are likely to be at the same price point. They'll have better performance, and lower power consumption (or at least lower power consumption when at a clock rate giving the same IPS), but ivy chips will be harder to get when Haswel is released, and you'll also have the problem of there being not so many motherboard reviews etc. If you want the PC now, it may be better to get it now, if you would rather wait, then you can, but you won't see a really major improvement.
OS: Windows 10 64 bit Professional
CPU: AMD Ryzen 5900X
RAM: 16GB
GPU: Radeon Vega 56
CPU: AMD Ryzen 5900X
RAM: 16GB
GPU: Radeon Vega 56
