chrisleeca

In theory the graphics card upgrade would give you higher FPS but most of the benefit of a 3070 would likely be crippled by the CPU. It's not just the CPU though it's the motherboard architecture, memory and storage performance. At least if you start with a newer base the 1070 is still going to work. You won't get much of an FPS boost but loading times will be reduced. As nishank93 said i'd consider zen2 as an option for gaming. Most of the Zen2 chips have more than enough CPU power to handle the higher end GPUs and you may just end up throwing money away for not much gain with Zen3, especially at launch.

I wouldn't recommend this approach at least not for the CPU fan. Yes, it will remove the fluctuations but you are doing this by decoupling the fan from the CPU temps. So the CPU fan will no longer adjust cooling as the CPU gets hotter. Maybe for chassis fans this makes more sense, although the CPU still provides a more immediate indicator of system load. I also find fans ramping up and down is distracting, but a consistent noise less so. The recommendation from geo3 is right at least in my experience. Use HWMonitor to check what range of temperatures your CPU jumps between from idle to light work loads such as web browsing. Make sure you have a flat line on your fan curve over that CPU temperature range, so the fans are not ramping up and down constantly. Repeat the same with heavy workloads, such as playing games and set a steep ramp up in fan speed above the light work load temperature range. This approach has worked well for my own setup.