I own an OCZ GameXStream 850W and i've been getting lockups frequently, and after troubleshooting through many guides, I noticed that speedfan was giving me a 11.14V reading on the +12V rail. BIOS readings showed a 11.80V reading. Is this within the safe limit, or should I switch over to a better PSU? I've been looking at the:
The ATX specification defines that your +12V outputs must be within 5% of their nominal voltages. Therefore your voltages should remain within this range: +12V (Min: 11,4V - Max: 12,6V). This means that your PSU performs out of specification.
On the other hand, here you have some good modular 750W PSUs:
Taking in mind the price difference, I recommend you to go for the ANTEC TruePower 750W.
It presents a great efficiency (80 Plus Bronze certified) and a very good voltage stability (voltages are close to their nominal values). Moreover, the ripple and noise levels are extremely low.
It comes with semi-modular design (it presents too many cables permanently attached to the PSU). The modular connector board comes with 5 extra electrolytic capacitors from Chemi-con. Moreover, all wires are 18 AWG.
It supports even two very high-end video cards that require two power connectors each due to the four (6+2)-pin PCIe connectors. They get the power from two 25A rails (all for themself). This PSU is SLi certified by nVidia.
There are four independently regulated +12V rails rated at 25A each one (over current protected). The max. combined +12V rating is 62A (744W).
All electrolytic capacitors are Japanese from Chemi-Con (in the primary there is one capacitor (560µF, 400V) which is labeled at 85º C while the cpas in the secondary are labeled at 105ºC). In the DC-DC converter they have used solid aluminum capacitors. This PSU is based on a DC-DC converter on the secondary (in charging of converting the +12 V output into +5 V and +3,3 V). This is the same concept used on the Seasonic M12D 750W and the CORSAIR HX750. It increases the overall efficiency of the power supply.
The PSU performs rather quiet at below 60% of its max. load. It has a 120mm double ball bearing fan from ADDA (AD1212HB-A7BGL). It is a high-speed fan with a maximum rotational speed of 2200RPM. The fan speed is automatically controlled by the internal component temperature due to an onboard PWM speed controller. Anyway, if you are a fanatic of the silence, you should look for another option.
Finally, It has five years warranty.
In summary, this is a very reliable product with very good overall performance. Taking in mind the affordable price, the ANTEC TruePower 750W would be my choice.
From reviews of your product, it sounds like the PS is certainly out of spec. If it is n warranty I would send it back. If that is not an option buy the Antec. Just curious, do you have a battery backup, ups or surge protector that you are connected to? If so try plugging in to the outlet direct and see if it makes a difference.