Confused about the PSU required..plz help

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qwerty_ashu

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Dec 25, 2012
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Hi all,

my pc config is:

i3-3220 (3rd gen ivy bridge)
Gigabyte H77M D3H (LGA 1155 socket)
1 x 4GB DDR3 1333 - RAM Kingston
500GB 7200 RPM WD HD
Samsung DVD / CD RW combo
sapphire AMD 7770GHz edition

please advice if the below mentioned PSU is good enough for my PC. If not please suggest a good one.

my PSU is 450W with following details
+5V - 29 A
+12V - 18 A
+3.3V - 30 A
-12V - 0.5 A
+5VSB - 2 A

3.3V & 5V = 85W max.


P.S. Monitor samsung LED 18.5" ..res 1366x768
 
Solution
For a system using a single Radeon HD 7770 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 23 Amps or greater and have at least one 6-pin PCI Express supplementary power connector.

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...

Lucam

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Jan 5, 2013
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I suggest getting a 550w PSU made by Seasonic as they produce the most reliable and high quality PSU's out there. The recommended power supply for the 7770 GPU is 500w. It's best you don't even use your computer with that GPU until you get a better power supply. You run the risk of destroying some of the components.
 
For a system using a single Radeon HD 7770 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 23 Amps or greater and have at least one 6-pin PCI Express supplementary power connector.

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 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).

Your PSU looks like its an old design that is biased towards the +3.3V and +5V rails. Its +12V rail is insufficient.

Where (i.e. which country and/or vendor), do you purchase your computer components from ?

What is your PSU budget ?
 
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joeh_87

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Aug 25, 2011
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18A on the 12V rail is cutting it a bit fine with such setup imo. if i'm correct just about every piece of Hardware runs through the 12v now adays.

My 450W PSU i had a 7850 & 5770 before the 7850 running on had 30Amps on the 12V rail

a good 500-555W should be fine leaving headroom. as Lucam said Seasonic/Corsair/Ocz all realiable PSUs
 

Malinak05

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Jan 3, 2013
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Those online "calculators" are very different from each other (my experience when getting similar system like that yours).
You will be fine, but no overclocking. Another disadvantage - you won't be (probably) able to run higher class graphics cards later, if you were thinking about that.
I'm suggesting to get Seasonic at 550 or 600W to get the possibility to change the GPU in 1-2 years.
 


Hi - as ko888 already explained, you need more than18a on
the +12v rail. Is it possible you have more than one +12v rail?
Check your documentation or the sticker on the side
of the PSU. If you only have one +12v rail then you will need
to get another PSU to run your 7770.

Tom



 

qwerty_ashu

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Dec 25, 2012
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Sure ... given ur suggestions guys i will check out other PSUs.

Please suggest the required +12V amperage rating for my system build and i will buy a new new PSU accordingly.


thanks.
 

+5V rail is still used for disk drive logic, low-voltage motors, PCI cards, USB ports

+3.3V rail is used for motherboard chipsets, some DIMMs, PCI/PCIe cards, some SATA devices, other miscellaneous logic chips

On PSUs that have hardwired output cables the +5.5V wires are colored red and the +3.3V wires are colored orange.

On the modern PSU designs the +3.3V and +5V rails are derived from the +12V rail using a DC to DC converter.
 

The CoolerMaster Thunder 450W (RS-450-ACAB-M3), with its maximum combined +12 Volt continuous current rating of 30 Amps and with one (6+2)-pin PCI Express supplementary power connector, is more than sufficient to power your system configuration with a single Radeon HD 7770 GHz Edition graphics card.
 
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