I'm wondering if my Corsair CX500 Modular is powerful enough to run my system with an i5 3570k (currently not overclocked, though info on that possibility would also be appreciated) and an AMD 7870 or AMD 7850. Not planning on crossfiring just yet. Any help would be greatly appreciated, thanks.
For a system using a single reference clocked Radeon HD 7870 GHz Edition graphics card AMD specifies a minimum of a 500 Watt or greater power supply. The power supply should also have a maximum combined +12 Volt continuous current rating of 28 Amps or greater and have at least two 6-pin PCI Express supplementary power connectors.
For a system using two Radeon HD 7870 GHz Edition graphics cards in 2-way CrossFireX mode AMD specifies a minimum of an 600 Watt or greater power supply. The power supply should also have a maximum combined +12 Volt continuous current rating of 40 Amps or greater and have at least four 6-pin PCI Express supplementary power connectors.
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.
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).
Corsair CX Series Modular CX500M (CP-9020059-??)
• maximum combined +12 Volt continuous current rating of 38 Amps
• two (6+2)-pin PCI Express supplementary power connectors
• sufficient to handle your upgrade to a single Radeon HD 7870 GHz Edition
If you keep your Intel Core i5-3570K overclock below 4.6 GHz you shouldn't need to bump up the PSU's +12V rail's recommended capacity.
Depending on the brand and model of Radeon HD 7870 GHz Edition graphics card, overclocking will usually increase power draw from the +12V rail(s) by 8 Watts to 20 Watts depending on magnitude of stable overclock attainable.