Getting more +more confused about psu's.

[TechnoCorruption]

Right well after my 400w Enermax Liberty went bang I phoned up and got an rma number which means I am back in the market for a decent power supply, I have up to £100 to spend and even though at the moment the rig is fairly basic, in the next couple of months I will be moving to a dual core Intel and a X1800/X1900.

So the power supply has to be pretty powerful, now this is where I got confused, I always though that more amps on the 12v line was what to look out for combined with high output power, my 400w Liberty had 2 12v rails of 20a but looking around it appears that the Seasonic 600w only has 2 12v rails of 18a, so which would give the best power.

Im guessing that even though a rail is rated at say 20a it might not be able to supply that all the time if its under 500w this is where I started to get confused, I dont mind about dual rails psu's because even if I did go cf/sli in the future, its not hard to get a pci-express adapter and put 1 on a seperate rail.

So what do I need to look out for and what recomendations do you have for a decent supply which will last a while, should I bite the bullet and try another Liberty or maybe look for something else.

 

[semi-pro waster]

You could get another Liberty if you wanted as I think overall they are pretty good. The individual rails don't necessarily combine to give exactly what a simple addition of rails would make you think e.g. a PSU with 20A on 12v1 and 18A on 12v2 may not give 38A total, it is more likely to be 33A or 34A.

I'd suggest that you also look at Tagan Easycon PSUs as you can manually choose either single or dual rail if you want.

 

[Dutch Guy]

my 400w Liberty had 2 12v rails of 20a but looking around it appears that the Seasonic 600w only has 2 12v rails of 18a, so which would give the best power.

A PSU can only give full power if the power is distributed among the 3.3V, 5V and 12V rails.

Propably the Enermax Liberty 400W has strong 12V rails and weaker 3.3V and 5V rails compared to a 600W Seasonic which is actually good for todays computers as the CPU and GPU(s) actually take most, if not all, power from the 12V rail.

The Liberty 500W has 2x22A on the 12V rails but a maximum of 32A on both rails, that means that if you load one rail with 22A the ther can't give more than 10A, you can never have 44A

If your plan is a dual core Intel and X1900 I would get the highest rated one your budget allows.

 

[TechnoCorruption]

Thanks for the replies, I have had a look around at the 580w Tagans, they seem to supply 2 12v rails of 20a with the ability to combine them to 35a single rail. I had a 480w Tagan in the past and never had 1 problem with it so I might decide on a 580w version.

Looking about though there seems to be two versions of the 580w, a U15 + a U22, is the only difference between the two the fact that one is modular and one isnt, I have had a look at Tagans website and they both have the same power and the rails switch.