24 Amps on 18A + 18A psu?

[coolpurplefan]

This might be a useless question but I have a Fortron Blue Storm II 500 watt power supply with:

+3.3V 30A
+5V 30A
+12V1 18A
+12V2 18A
-12V 0.8A
+5Vsb 2.5A

I'm trying to choose between various video cards which require up to 24 Amps on the 12V rail. I'm just a little confused as to whether 18A on a single rail is enough or if the video card will draw amps from both rails.

This is on a machine which will likely be using a dual core processor, 4 GB RAM, one HD and one DVD-RW.

 

[The Boston Dangler]

the video card will draw from only 1 rail.

 

[coolpurplefan]

So if it only has 18A on each rail will it work? I don't know what the card will use and what the rest of the computer will use.

 

[Mark R]

The usual way that such cards are designed is to take upto 75W (approx 6 A) from the motherboard and up to 150 W (approx 12 A) from the connectors.

Most PSUs are designed with 1 rail going to the mobo, and 1 rail going to the extra power connectors on the graphics card. This results in roughly even power distribution, once the power of the CPU, etc. is taken into consideration.

 

[coolpurplefan]

OK, 24-6=18 so I'm assuming it will work since I did not get a straight answer.

 

[theAnimal]

This might be a useless question but I have a Fortron Blue Storm II 500 watt power supply with:

+3.3V 30A
+5V 30A
+12V1 18A
+12V2 18A
-12V 0.8A
+5Vsb 2.5A

I'm trying to choose between various video cards which require up to 24 Amps on the 12V rail. I'm just a little confused as to whether 18A on a single rail is enough or if the video card will draw amps from both rails.

This is on a machine which will likely be using a dual core processor, 4 GB RAM, one HD and one DVD-RW.

The Blue Storm II has about 34 total amps available on 12V which is more than the recommended 24A (for the system not just the video card).

the video card will draw from only 1 rail.

The video card will draw up to 75W from the PCIe slot and the rest from the PCIe connectors (up to 75W for 6 pin and 150W for 8 pin). The connectors could possibly be on different rails (The Blue Storm II has the PCIe connectors split between the 2 rails.).

 

[The Boston Dangler]

yeah, i forgot about the 75W slot power