How to interpret 12v rail specs on PSU

[pong3d]

I was looking for a PSU with at least 18A on the 12v rail and came across some specs that had 15a on each the 12V1DC and 12V2DC rail. What is this and can I combine the two for 30a total?

 

[KoolDrew]

+12v@18A is a little low. Try to at least get +12v@24A. As to your question yes. Many PSU's today have dual +12v rails. It is basically for improved voltage regulation. Remember numbers are not everything though. Make sure to get it from a good manufacturer. If you can post what PSu you had in mind or what you are looking for or what you are powering I or someone else can help you.

 

[Navid]

Each 12-V rail can provide a maximum of 15A. If you hook up components to one rail that need more than 15A, you are out of luck.

If you hook up components to each rail that need a total of 15A, you will get a total of 30A (15A from each rail). That is the only way you can get more than 15A from the supply.

 

[ArnoldLayne]

Are you talking about the neo4? That "it should be greater than 18A" recommendation is for a single rail. If you look at the MSI Neo4 Platinum test report, they have 300W and 350W power supplies that tested OK. I wish MSI would publish a recommendation for dual rails (or if they did I would like to know where it is!).

I would say check out a support forum for the board you are looking at and see what PSUs others are using successfully.

With ATX 2.0 and two 12V rails, the cpu is on a rail by itself. You can't directly add your two rails to get a single rail equivalent, but 15a on two rails is probably sufficient.

My power supply only has 18A on each rail (Antec Truepower 2.0 480W) and so far it hasn't blown up.

 

[Operandi]

One rail is dedicated to the ATX connector, the other rail is used for any peripheral connections; HD's, externally powered graphic cards ect. For the record a single 18A 12V rail will run just about any single CPU non-SLI system you could put together, let alone two 18A rails.

 

[imported_Kensai]

Now, if you're going SLI get the PC Power & Cooling's 850W Quad rail PSU. One rail for the CPU, one rail for each video card and one rail for everything else. Now that's mean.