CPU overclocking requires a large
investment via a more expensive
motherboard (Z97/Z170 etc), aftermarket
cooler and CPU(Intel K models).
For gaming, CPU overclocking provides very
little benefit (even
in "CPU intensive" games like ARMA 3) and instead that
money should always be put into the GPU
(unless you're using a T1 GPU which start at $600+ USD
inside the current generation). For
other games its effectively no difference (including
TL;DR Backblaze and anecdote are irrelevant and
intellectually dishonest when talking about HDD reliability
(there is no valid data available).
For Streaming you have two real choices:
Stream using a GPU based technology (NVENC, VCE(legacy),
for Nvidia, AMD and Intel GPU's respectivley) or build a
dedicated capture system with a capture card. CPU streaming
is not viable or acceptable.
Multi-GPU solutions (SLI and CrossFire)
are only ever worth using with top-tier cards (such as the
GTX 1080). For weaker cards, a step up to a stronger single
card will bring better performance than adding another
weaker card into a SLI/CrossFire setup. In addition,
SLI/CrossFire also have generally poor support, to the
point where some games perform worse in multi-GPU setups.
In addition multi card setups increase power consumption
and temperature linearly with the amount of cards added.
Techpowerup found that "only 6 out of 16 tests are taking
advantage of the second card." for Crossfire Rx480's(Thanks
Nvidia isn’t any better.
Future proofing is about hardware not
becoming obsolete however due to generational release
cycles this is impossible. The closest thing you can do is
make smart choices today and pocket some money for an
Windows (especially modern versions like
10) are very good when it comes to handling drivers, as a
result the only drivers you should be installing are those
for things that don't work (and always grab the latest
drivers from the manufacturers website, so throw away that
disk!); except for GPU drivers which you should always keep
up to date!
<fwaggle> look i'm already set on
riding a motorcycle without a helmet i'm just looking for
advice on which seatbelt is best for my hayabusa, not a
lecture on helmets thanks
For the information we have avaliable
even after all the troubles that the AM4 platform has had
we're seeing generally
better metrics of lower fps even with Nvidia drivers
presenting issues 
Retail Windows is the only version of
Windows most people should consider as it can be
moved between systems, unlike OEM Windows which is bound to
the motherboard it is first activated with.