PSU upgrade in old system

jimmyduckie

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I have an old system but still functional
Motherboard: P4VM800 ASRock (atx12v 1.1)
PCU: Intel P4 2.8 Northwood

I want to install the SAPPHIRE RADEON HD4650 1GB AGP Graphic card and i need to upgrade my PSU.
So, i want to buy the Corsair VX550 PSU model.

But i wonder if this model is full compatible with my old motherboard which i already use.
I read the product overview, but notes only ATX v2.2 & 2.01 compatibility.
As I know, ATX12V v1.1 and v2.01 have specific differences. The main cable is 20pin in v1.1 and 24pin in v2.01. The P4 cable is 4pin in v1.1 and 8pin in v2.01. However this PSU model has flexible cables 20/24pin) and (4/8pin).
Also, ATX12V 2.x brought a very significant design change regarding power distribution. When analyzing the then-current PC architectures' power demands, it was determined that it would be much easier (both from economical and engineering perspectives) to power most PC components from 12 V rails, instead of from 3.3 V and 5V rails.
Before this, in v1.3 -5V rail is prohibited and Slightly increased the power on 12 V rail.
So I believe, that the real question is, if the rails in the new PSU models atx v2.x, can power an old ATX v1.1 motherboard, without causing damage, because of the power increase and the other minor differences.

Could you inform me if there is compatibility between PSU atx v2.01 with ATX v1.1 motherboard?

Thank you for your time
 
Solution
The wiring scheme is still identical so you can safely power an ATX 1.x motherboard off of a 2.x PSU and vice versa, the computer will only draw as much power from the PSU as it needs so you dont need to worry about the power increase because its just an increase in available power. The 550VX will also have plenty of power on the 5V and 3.3V rails to power your older system so it will work quite well.
The wiring scheme is still identical so you can safely power an ATX 1.x motherboard off of a 2.x PSU and vice versa, the computer will only draw as much power from the PSU as it needs so you dont need to worry about the power increase because its just an increase in available power. The 550VX will also have plenty of power on the 5V and 3.3V rails to power your older system so it will work quite well.
 
Solution

jimmyduckie

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Thank you for your comment.
However, i just receive an answer from Corsaire Customer Service (Technical dpt): "I do apologize but it will not work as our PSU will not support that version."

So, I'm realy confused...
Any idea?

 

jimmyduckie

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Well finally I took my chances and I bought Corsair VX550.
It powers my old motherboard just fine (so far).

So, I believe that the Corsair Technical Support missed something.

Just for your info...