Making a 600W PSU by joining 2x300W. Do I need that?

I currently have a 2x300W PSUs, rated:
+12V - 10A
+5V - 30A
+3.3V - 20A
+5VSB - 2A

And a vision struck my mind, to link them parallerly (spel?), but linking ALL the rails, So the amps would double in all of them. But I've been wondering if it's worth it. Couple of questions though:
1. I assume the +5V rail is used for powering the cpu (amd), how is it with intels, and what is the 3.3V one for anyway, rams? chipsets?
2. Will shortening the ATX plug's cables do much good to my rails (+5V is at 4.6-4.9V, and the 3.3 is at ~3.5V)
3. My sys consists of DVD,CD-RW,3x7200 HDDs, 3.5" floppy. I'm curious about my +12V rail. I'll be going fully watercooled shortly, and assuming I'll have 6x120mm fans (0.5A each) and 2x80mm (0,15A each) plus a neon or two, so that'll be like ~3,5A more for the +12V, will my psu be able to take that (it did with 2x120, 2x80) or will it just FRY?
4. What is the aproximate power consumption on +12V for 7200rpm, dvds, cd-rs
5. What the +5
In general, is it worth to make that 600W PSU (assuming the trick is possible with all the rails) just for having a power reserve. What are the real advantageous (apart from the obvious)...

hi witchhunter, welcome to the forums!

Unfortunately, it's not possible to combine power supplies like that- the power ratings do not 'add'. But, you can do something almost as good- join them to start simultaneously! You can hook your motherboard up to one of them and all your fans/drives/etc up to the other one. Net result is almos the same thing as having one real 600watter!

check out

this thread for info on how to do it.

I thank you for the thread as well as I have cut an opening for the psu and need to install it somehow. You have provided the answer. Thank You.

Nice to be here, thanks.

Still, yes I know how to make them start simultaneously, but on the other hand, there'sthis article about joining PSU. I also know, that you can join single rails, let's say +5V from on and +5V from the other. And serially you'll get 10V 30A, parallerly (spel?) it'll be +5V 60A. And what I as thinking was to join all the rails from the psu, and with this I had doubts whether it'd work. So, why not?

Welcome to the forums.

If you carefully read the Procooling article, you'll note that the method used id for 2 AT PSUs, not ATX. You really don't want to try it with ATX PSUs.

True, they used AT. Now, just out of sheer curiosity, why wouldn't that work with ATX?