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How much PSU do I need?

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March 2, 2013 2:07:33 PM

I am building a computer for the first time, and I'm not sure how many watts I will need, help? Here are my planned parts:

Intel i7 3770k @3.5Ghz
Gigabyte GA-Z77X-UD3H
XFX Radeon HD 7970
16GB (2x8) RAM 1600 DDR3

How much PSU power do I need?

More about : psu

a c 297 ) Power supply
March 2, 2013 2:13:07 PM

Yizbenlazzer said:
I am building a computer for the first time, and I'm not sure how many watts I will need, help? Here are my planned parts:

Intel i7 3770k @3.5Ghz
Gigabyte GA-Z77X-UD3H
XFX Radeon HD 7970
16GB (2x8) RAM 1600 DDR3

How much PSU power do I need?


Hi - realhardtech suggests a quality 550w (min 31a on +12v rails) PSU
for a system with a 7970. You can get by with less if it's a quality
brand and has sufficient amps on the +12v rail(s).

Look for a quality 550w unit from brands such as:

Seasonic, XFX, Antec, most Corsair's, PC Power & Cooling,
Rosewill Capstone/Fortress series, Silverstone, most Enermax.

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a c 1192 ) Power supply
March 2, 2013 2:37:17 PM

For a system using a single AMD Reference Design Radeon HD 7970 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 39 Amps or greater and have at least one 6-pin and one 8-pin PCI Express supplementary power connectors.

For a system using two AMD Reference Design Radeon HD 7970 graphics cards in 2-way CrossFireX mode AMD specifies a minimum of an 750 Watt or greater system power supply. The power supply should also have a maximum combined +12 Volt continuous current rating of 58 Amps or greater and have at least two 6-pin and two 8-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.

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.

The +12 Volt continuous current ratings, I've specified, allow the system to be able to survive running any GPU stress testing utility like Furmark. I'm not stupid enough to assume that people don't run these stress testing utilities. The power supply should always be able to handle the worst case power draw scenario.
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March 2, 2013 2:45:44 PM

Go get a TX 750W PSU form Corsair or XFX pro series 750w full modular and you won't have any problems. Trust me I got a gtx 690 and a unbranded cheap 850w psu and it just couldn't handle it under load so now I have to buy a new one.
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a c 297 ) Power supply
March 2, 2013 3:04:14 PM

ko888 said:
For a system using a single AMD Reference Design Radeon HD 7970 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 39 Amps or greater and have at least one 6-pin and one 8-pin PCI Express supplementary power connectors.

For a system using two AMD Reference Design Radeon HD 7970 graphics cards in 2-way CrossFireX mode AMD specifies a minimum of an 750 Watt or greater system power supply. The power supply should also have a maximum combined +12 Volt continuous current rating of 58 Amps or greater and have at least two 6-pin and two 8-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.

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.

The +12 Volt continuous current ratings, I've specified, allow the system to be able to survive running any GPU stress testing utility like Furmark. I'm not stupid enough to assume that people don't run these stress testing utilities. The power supply should always be able to handle the worst case power draw scenario.


Hi ko - where did you find the 39a on the +12v rail? The site that I've been using
lists 31a for the +12v. If they are that far off I need to quit using them.

Thanx
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a c 1192 ) Power supply
March 2, 2013 3:12:10 PM

toyftw said:
Hi ko - where did you find the 39a on the +12v rail? The site that I've been using
lists 31a for the +12v. If they are that far off I need to quit using them.

Thanx

The minimum of 31 Amps is for handling a typical gaming load.

Review sites seem to ignore the fact that some people actually run GPU stress testing utilities. I've never regarded that running GPU stress testing is typical usage but I won't ignore the fact that it's done.

If the PSU is unable to handle the power draw during the test the power supply will most likely shut down if it has the proper protection circuits built into it.
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a b ) Power supply
March 2, 2013 3:13:57 PM

Yizbenlazzer said:
I am building a computer for the first time, and I'm not sure how many watts I will need, help? Here are my planned parts:

Intel i7 3770k @3.5Ghz
Gigabyte GA-Z77X-UD3H
XFX Radeon HD 7970
16GB (2x8) RAM 1600 DDR3

How much PSU power do I need?


like toy said, a solid 550w+ will do the job
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a c 297 ) Power supply
March 2, 2013 3:33:59 PM

ko888 said:
The minimum of 31 Amps is for handling a typical gaming load.

Review sites seem to ignore the fact that some people actually run GPU stress testing utilities. I've never regarded that running GPU stress testing is typical usage but I won't ignore the fact that it's done.

If the PSU is unable to handle the power draw during the test the power supply will most likely shut down if it has the proper protection circuits built into it.



Gr8 - thanx!
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