Seasonic is vastly superior to Zebronics.
For a
system using a
single reference design Radeon HD 7850 graphics card AMD specifies a minimum of a 500 Watt or greater system power supply. The power supply should also have
a maximum combined +12 Volt continuous current rating of 23 Amps or greater and have at least
one 6-pin PCI Express supplementary power connector. Some of the non-reference design Radeon HD 7850 graphics cards require at least two 6-pin PCI Express supplementary power connectors and the maximum combined +12 Volt continuous current rating will need to be increased up to 29 Amps depending on brand and model of the graphics card.
Total Power Supply Wattage is NOT the crucial factor in power supply selection!!!
Sufficient Total Combined Continuous Power/Current Available on the +12V Rail(s) rated at 45°C - 50°C ambient temperature, is the most critical factor.
Overclocking of the CPU and/or GPU(s) will require an additional increase to the maximum combined +12 Volt continuous current ratings, recommended above, to meet the increase in power required for the overclock. The additional amount required will depend on the magnitude of the overclock being attempted.
You may find power supplies on the market that supply more than enough Wattage to run the system. However, some of them lack Sufficient Amperage capacity on the critical +12 Volt rail, which is necessary to properly power the critical components in the system (i.e. CPU and GPUs). This is the reason why graphics card manufacturers may overstate the power supply wattage, usually by at least 50 Watts, in an attempt to take into account some of those power supplies that have the weaker +12 Volt rail(s).
The
Seasonic S12II-620 Bronze (SS-620GB), with its
maximum combined +12 Volt continuous current rating of 48 Amps and with
one 6-pin and one (6+2)-pin PCI Express supplementary power connectors, is
way more than sufficient to power your system configuration
with a single Radeon HD 7850 graphics card.
Even the Seasonic S12II-520 Bronze (SS-520GB), with its
maximum combined +12 Volt continuous current rating of 40 Amps and with
one 6-pin and one (6+2)-pin PCI Express supplementary power connectors, is
way more than sufficient to power your system configuration
with a single Radeon HD 7850 graphics card.
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