I was looking at this power supply however despite good reviews on NewEgg and decent reviews elsewhere, people are saying not to get it.
This is because of the voltage regulation apparently. Most power supplies test in at a 1.2-1.4% difference at +12V. This one tests in at 2.1%. Looking up my parts, everything is rated to work with differences up to 5%.
So my question is, does 1.2% vs 2.1% matter when both are well within the parameters given by my parts?
Are there others reason why this PS is not to be recommended? (I'm getting it for $150 no shipping)
The Coolermaster 1000W PSU is an average quality PSU. While PC hardware components are rated to "work" with voltage variations of 5%, the more you push the hardware the more important voltage stability becomes. It's unlikely that 1.2% vs. 2.1% variation on the 12V rail will make any tangible difference.
If you actually need a 1000W PSU then this unit may be OK for the price but it just doesn't have as good of build quality and electical efficiency as some other brands.
If your intentions are too OC then buy high quality components. If you are not going to OC then average components will probably be okay though if as stated you really need that much power then maybe you should consider a higher quality unit.
Here is a LINK that may help you to decide what to buy.
Who is claiming that most power supplies test within 1.2-1.4% voltage regulation on the 12 V rail? Most units will test within about 3% regulation, Jonnyguru considers 1% regulation to be excellent and 2% to be above average, and most of the high end units they test which have pretty good regulation come in around 1-2%, 2.1% isnt bad by a long shot its still much much better than is required and much better than a cheap unit will give you.
In that units review on jonnyguru it was doing a bit over 3% regulation which is about average which is disappointing considering the pricing of the unit.
Now, loose voltage regulation doesnt necessarily make it a bad unit, it stays in spec in all regards unlike the GX series, but its just not a great unit. What are you going to be powering there may be a cheaper but better unit that will handle the system just fine, very very few configs need a 1kW unit.