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PSU 12V Rails question

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Posted · Original PosterOP

So I have a crappy power supply in my new used computer right now, and lucky as I am the HD 7850 that I had in there died (not due to the PSU but due to age, it was a VTX3D model that was acting sketchy since the beginning of it's life span)


I want to upgrade my PSU and my GPU since anything more than the 7850 I had will be too much for it (a weird 450W Sharkoon unit with a 1 6pin pcie connector)


So I was looking at this power supply, it's a 500w unit that's also 80+ certified and it's not available in America so saying what model it is will cause more confusion than anything else.

It's a Chieftec unit but it's basically a rebranded Delta PSU and they are known for making quality units. I know that Chieftec is a hit or miss brand but the specific model I'm looking at (Gpa-500s8) seems to be actually popular where I live and pretty much reliable for a lot of people talking about it online on forums.


Here's the question though. I'm looking to upgrade to an MSI r9 270x 2G GPU and the requirements say that it needs 30 amperes on the +12V rail(s) and atleast 500w to run without problems (I'm actually saying this from my head I'm not too sure if the information is correct right now :D ) That PSU unit in question has got a 6+2 pin pcie connector though while the R9 270x requires 2 6pin connectors. Also the PSU functions on two 12V rails, one of which is 24A and the other is 21A. Would the PSU considering that it's 80+ certified and that is relatively not that bad be able to power my GPU using either a molex to 6 pin adapter or a 8 pin to 2 6pins adapters, the main question here being the amperage (does it matter that the 12V is split into two rails since they combined add up to 45A?)


Thanks m8s.

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30A * 12V = 360W


It'll be fine, they are taking into consideration worst case scenario for total system power requirements. An R9 270x is not going to pull 360 watts from the PSU by itself. unless it's on fire. even then, it'll be short lived.

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Depends on what the system needs. My cards need 42 amps on a single rail. Tried one that split it but the second rail also shares its power with other components. So the pc would crash with anything was over clocked. 


Id get a quality single rail psu if possible. 

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I saw that you will buy the same type of card i have an ASUS R9 270X DirectCU II TOP and a Corsair VS450 comming from a thread on GPU's about not be able to overclock a guy from there said that my PSU isn't enough but im straggling to understand why if this card needs 30A from 12V and my PSU is giving 34A and according to http://outervision.com/power-supply-calculator i need for my system 


Amperage (combined)
+3.3V +5V +12V
9.7 A 10.5 A 31.4 A
85 W 377 W



Then why my PSU isn't enough for my System?

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