[tmarat]

Originally Posted by Oklahoma Wolf

Not sure about the 8 to 4 pin adaptor actually - you might have to check around for them, or give Newegg an email. The PCI-E adaptors generally plug into two drive molexes each, to make sure the load is distributed on more than one 12v wire. Each side of the adaptor should ideally run to a seperate chain of molexes on the PSU itself.

Needless to say, the new PSU will have to have a few of these drive molexes to make sure you have enough left over for actual drives, though for hard drives Y adaptors will work fine. Just be sure to distribute the load evenly between each molex chain on the PSU.

Actually, I would suggest the Fortron/Sparkle FSP550-60PLG model for this endeavor with its single 36A 12v line - that way you can mod the 8 pin EPS connector for extra 12v kick at the PCI-E connectors if you want (won't work on the dual 12v unit).

I moved this post to a separate thread as it was not about volt modding.

In the following article that PSU is tested in an SLI configuration. Two PCIE connectors were derived from 8-pin EPS connector, or at least I understood so.
I am a little confused as if you do so, then you cannot use the second 12v rail to power the cpu.
http://ht.hardwareanalysis.com/content/topic/38623/
"The power supplies designated with a * are needed if you want to run the A8N-SLI with an Athlon 64 FX 53 or 55 processor, two GeForce 6800 Ultras and two or more high capacity Serial-Ata drives. However they need to be modified in order to convert the 8-pin 12-volt connector, coming off of the 2nd 12-volt rail to two 6-pin PCIe power connectors, this is a simple procedure that means extracting the pins from the original connector and splitting them out to two 6-pin PCIe connectors. These will be connected to the GeForce 6800 Ultras directly, hence powering them off of their own 12-volt rail within the power supply. From our testing this is the only way to guarantee absolute stability. Take notice that when running SLI the EZ-Plug must also be connected to guarantee stable operation."

[Oklahoma Wolf]

On the Fortron FSP550-60PLN, 12v1 will be for drives and 12v2 will be for CPU and motherboard (at least that's the info I have). Modding the 8 pin EPS connector on this one will result in motherboard, CPU, and both SLI video cards loading down the 12v2 rail, which may become overloaded. This is why I suggested using the FSP550-60PLG instead, where you wouldn't have to worry about it.

http://www.newegg.com/Product/Produc...82E16817103478

btw - forgot to mention it earlier, but welcome to the forums

[tmarat]

Thanks alot for your help.

I want a psu with future potential. I do not want to buy a 1 rail psu. Can you suggest a psu within 100-120$, with double rails and sli compatible?

[Oklahoma Wolf]

That's a bit tricky... most of the SLI ready units out there are over $120. Found one though.

http://www.newegg.com/Product/Produc...82E16817103462

I don't often recommend Enermax these days, but it does meet your requirements.

Edit - found a better price on the non-PFC version:

http://www.ewiz.com/detail.php?name=PS-E565PVE#

[tmarat]

I read somewhere that Fortron FSP550-60PLN, being a server psu, is rated at about 50C, compared to about 25C on normal ATX psu units. It that true?
Which is better BLUESTORM 500w or Fortron FSP550-60PLN?
I can have the Fortron FSP550-60PLN for about 110$. FSP - BLUESTORM 500 WATT for about 100$.
Bluestorm looks cool compared to FSP550-60PLN. But I care more about power, than looks and noise is not a big issue.

I read that you can actually insert the 8-pin 12V connector onto the 4-pin power connector in the motherboard if there is enough space around it. In a DFI SLI-DR, there isn't http://www.pcper.com/image.php?aid=1...=board_big.jpg
Its just above the ATX connector. What if I simply cut or crush the unnecessar pins? Will it work?
"the easiest way to search for such an animal is to look for an EPS12V supply, those are a slightly different spec Intels Server System Infrastructure and the connectors are compatible for the v2.0 mains formfactor.org having adopted the mains from there, but the auxillary connector (Intel 2x2 +12V) is transformed in the EPS12V spec to an 2x4 eight pin, and again it can be used directly if there is clearence, but I know of no converters from 8 pin to 4 pin, as of yet (though I think I might start a company )
now most ATX12V v2.0 supplies are also EPS12V compliant and they just have different wiring harnesses, but when they are listed as ATX12V supplies, they often dont bother to list the +12V individual rails but would in their EPS12V wiring harness trim"

[Oklahoma Wolf]

The 550w is electrically superior to the AX500-A, due to the independant voltage regulation design. These are rated as 550w @ 30 degrees, 500w @ 50 degrees. The AX500-A is 460w @ 25 degrees.

Not sure how well it'll work to leave pins hanging off the 8 pin connector - I would probably do my best not to damage the connector itself in case I needed it for a future upgrade (some boards are now showing up that need the 8 pin).

[larva]

I personally feel the two 12V line 550 Fortron/Sparkles are the most powerful dual 12V line supplies to be found. I suspect from the wording of your quote in the original post that the people recommending wiring them up this way have actually done it, and the positive results indicate this is the best way to skin this particular cat. I suggest you continue to pursue this supply, and email Fortron and/or Sparkle if you have any doubts about which connectors are powered from which rail.