With the power that even Intel's integrated GPUs have nowadays you won't notice anything odd or under-performing with either of those platforms you mentioned. Sure, if you get a "proper" discrete GPU from AMD or Nvidia it'll help things work better in terms of serious graphics requirements aka gaming but not much else, at least not from an SDR perspective.
People regularly do SDR duties using 10+ year old machines still running XP so yeah, those i7 or i8 based machines will absolutely be able to handle anything you'd like to experiment on. While it's not 100% required, my advice is buy more RAM if it's within your budget to do so, say 16GB
so you have it and not at a later time when you may find yourself in a situation that could stand from having it. These days RAM isn't necessarily super expensive but the pricing fluctuates pretty wildly, especially if there's some natural catastrophe affecting the Asian regions of the world where such components are manufactured.
And get a nice display as well while you're able, or two as SDR ends up being a visual-centric way of monitoring nowadays with the spectrum and waterfalls that add to the hobby and have created a paradigm shift towards this new way of doing things. I've never been a big fan of multiple physical monitors but with SDR it can come in handy having SDR app of most any kind open on one monitor working in progress while still having another to do the typical computer "stuff" like web browsing, coding, reading, etc.
Alt+Tab = the best keyboard shortcut ever especially if you're a pretty serious multi-tasker.
