Power supply upgrade mean a higher electric bill?

The electric bill goes up or down is solely determined by the efficiency of the new power supply. Greater power efficiency means a lower electric bill because more of the AC power is converted into DC for the computer, rather than wasted as heat. The savings can really add up over time.

The true about power supply wattage claims

To properly compare power supplies, wattage claims must state the maximum ambient temperature for continuous, full-load operation (not half). Unfortunately for the consumer, this information is usually withheld, opening the door for manufacturers to exaggerate their wattage claims. They do so by assuming an unrealistic ambient temp of only 25°C (77°F), even though the actual internal power supply temp is at least 40°C (104°F). Since the proper full-load power supply rating is 15°C higher for home use and 25°C higher for industrial use, these power supplies produce 33%-50% less power than their advertise ratings.

Don’t lose power with modular plugs

Power Supply Modular plugs limit power by adding to electrical resistance (pin contact). The voltage drop can be as much as would occur in 2 feet of standard wire. Worse yet, modular plugs utilize delicate pins that can easily loosen, corrode, & burn, creating the potential for a major system failure. That’s why professional system builders specify uninterrupted wire!

An SLI certified power supply will always power high-end graphics cards?

If you really want to build something that pushes the bleeding edge, make sure you have the right power supply. Certified SLI Power Supply is not WARRANTY for Unlimited Power.

Should an ATX power supply be cooled with a 120mm fan?

Most low-noise ATX power supplies today utilize a top-mounted 120mm fan rather than a rear-mounted 80mm fan. The 120’s favorable reputation is based on the fact that under low to medium (30-50%) load conditions, The 120mm fan provides sufficient cooling at low RPM & low RPM fans are generally very quiet. problems occur with this design when the load exceeds 50%-60%. Because the 120mm fan consumes about 1.5″ of vertical space inside the PSU, heat sinks, capacitors, and other components are about 30% smaller in height compared to a PSU with a rear-mounted fan.

For systems that require more than 50% of the power supply’s capacity, a well-engineered PSU with a rear-mounted 80mm fan will provide superior performance & reliability (due to larger components) at a noise level comparable to a PSU equipped with a 120mm fan.

Are two power supply fans better than one?

No. A power supply with two fans doesn’t exhaust any more air from the case than a power supply with one fan.

Are multiple 12-volt rails better than a single 12-volt rail?

With all the hype about multiple 12-volt rails (ads claim that two rails is better than one, 5 is better than 4, etc.), you’d think it was a better design. Unfortunately, it’s not true!

Here are the facts: Large, single 12-volt rail (without a 240VA limit) can transfer 100% of the 12-volt output from the PSU to the computer, while a multi-rail 12-volt design has distribution losses of up to 30% of the power supply’s rating. Those losses occur because power literally gets “trapped” on under-utilized or none-utilized rails.

Source: http://www.pcpower.com/