What processor do you plan on using?
Only when that is known can you pick a motherboard.
Do not worry about pcie2/3/4.
Graphics cards are forward and backwards compatible and any difference in performance is miniscule.
Only when the motherboard is picked can you decide on ram.
400w is marginal for a psu for a GTX1060.
Look to 450 or 550w to allow for a future graphics upgrade.
More important is to buy a high quality psu.
Pick at least tier 3 unit from a list such as this:
Credit to @Starelementpokeand @Energycore for helping out with this long-awaited refresh of the old PSU tier list by Aniallation (who previously went several months without logging in), leaving the old list in need of help. This is simply an update of the list that was flawed in creation by the P...
linustechtips.com