Will Antec modular cables use different rails?

[CZroe]

I have two 78000GT cards that I need to power in SLi. My PC Power and Cooling Turbo-Cool 510 doesn't have 24-pin ATX, 8-pin +12v (AUX), PEG connectors, or dual PEG connectors for that matter... heck, I don't even think it has SATA. It was perfect for my last SLi system because it used standard Molex/AMP 4-pin instead of 24-pin ATX, standard 4-pin +12v instead of 8-pin, and both XFX 7800GT video cards each used a single standard 4-pin Molex/AMP connector instead of TWO or a PEG connector. It had just enough cables to dedicate one chain to each card and still have what I needed for the drives and the motherboard's 24-pin alternative connector.

Even though it was perfect for my last dual-core SLI system, it has to be retired for the new quad-core system... but this is a problem. These days, PSUs sacrifice Molex/AMP connector chains for at least two chains of SATA connectors and even more for PEG and dual PEG (Crossfire/SLi). So, both the motherboard and the PSU I'm using now have 8-pin +12v and 24pin ATX, but I am still using the same Molex/AMP-powered 7800GT video cards until the 8800GTS 640MB cards come under $300. Unfortunately, I can't find a PSU with more than two chains of AMP/Molex adapters despite knowing that my cards specifically need the entire chain dedicated to itself, especially seeing as how a normal 7800GT needs PEG connectors.

Now, I have a higher-wattage SLi certified Antec NeoPower to hold me off for now (and a 600w OCZ ready to go in when I get the 8800GTS cards). I considered getting PEG converters that convert them to 4-pin Molex/AMP but, considering that an adapter going the "other way" uses two AMP/Molex adapters from (likely) different 12v rails, I'd kinda expect to get the same out of it. All I can find are 1-to-1 reverse adapters. I will simply use these if I must, but I noticed that the PEG cables plug into the same connectors on the PSU as the AMP/Molex connectors. Are the rails split across connectors in a modular Antec PSU or would a Molex/AMP modular cable connect to a different set of pins inside? If a rail is set aside to pins that only the PEG connectors use, I still want to use those when converting considering that these will be used to power graphics cards. The adapters only provide 12v while a normal Molex/AMP provides 5v too. Might these video cards also tap the 5v rail for a little extra juice considering that they are using one Molex/AMP in lieu of two or a single PEG connector? If so, adapting a PEG connector to Molex/AMP for these sounds like a bad idea.

I guess I can always adapt some SATA connectors, but it different sockets on an Antec PSU provide 12v from different rails, that would be the simplest solution (buying more Molex/AMP modular cables).

 

[mpilchfamily]

Each line or chain as you are colling them are not on different rails. The 4 or 8 pin CPU power connector is on its own rail and everything else is split amoung and other rails the PSU may have. If you need more Molex then just get a few Molex y-adapters. There is no need to modify or change over SATA or any other power connectors to Molex. If you have the 500W Neo then it will provide more amperage on the +12v rails the that 600W OCZ. You will be better off sticking with the Neo when you upgrade to the 8800s.

 

[WobbleWobble]

The different sockets dictate which rail the voltage comes from.

I know with the 430W version of the NeoHE the 24 pin ATX cable and the 4/8pin CPU connector use one rail. The two sockets closest to the 24 pin ATX cable share one rail and the last three share another rail. Not sure if it's different for your higher wattage NeoHE. If you contact Antec support, they can tell you for sure.

 

[CZroe]

Thanks. I can't split off with Y-connectors because I only have two "chains" of three connectors each. I am not supposed to connect any of the other connectors on the chain if one is going to a video card. As a result, two video cards claim all six connectors. I'll check with Antec and, if they confirm for this model, I'll order more standard connector modular cables. Thanks again!

 

[mpilchfamily]

Wait a monute the video cards shouldn't be using the regular 4 pin molex connectors. The PSU will have 2 x 6 pin PCI-e connectors. Each of the 8800 GTSs will use one of those connectors. So you will have all 6 of the 4 pin Molex for your drives and fans. Do not try useing adapters for the PCI-e power connectors when the PSU will already have those connectors for you.

 

[mpilchfamily]

*Duplicate post*

 

[John]

Originally posted by: mpilchfamily
Wait a monute the video cards shouldn't be using the regular 4 pin molex connectors. The PSU will have 2 x 6 pin PCI-e connectors. Each of the 8800 GTSs will use one of those connectors. So you will have all 6 of the 4 pin Molex for your drives and fans. Do not try useing adapters for the PCI-e power connectors when the PSU will already have those connectors for you.

Originally posted by: CZroebut I am still using the same Molex/AMP-powered 7800GT video cards until the 8800GTS 640MB cards come under $300.

CZroe, if I were in your position I would also order 2 more modular sleeved molex cables from Antec so that you do not have to use adapters. I would also recommend selling the OCZ psu since your Neo is more than adequate for 8800GTS SLI + quad core.

 

[CZroe]

Originally posted by: mpilchfamily
Wait a monute the video cards shouldn't be using the regular 4 pin molex connectors. The PSU will have 2 x 6 pin PCI-e connectors. Each of the 8800 GTSs will use one of those connectors. So you will have all 6 of the 4 pin Molex for your drives and fans. Do not try useing adapters for the PCI-e power connectors when the PSU will already have those connectors for you.

"I am still using the same [standard 4-pin] Molex/AMP-powered [XFX] 7800GT video cards until the 8800GTS 640MB cards come under $300"

That's the issue... they don't accept PEG connectors and I was worried that I'd overload a rail if I just got more modular 4-pin Molex/AMP connectors. I was also worried that adapting PEG connectors to standard connectors wouldn't be adequate considering that the cards may use +5v to make up for the lack of PEG power. If different 4-pin Molex/AMP cables plugged into different sockets on the modular PSU go into different rails, then it's "no worries. problem-solved." I'll just buy a couple more. Thanks!

Because Molex/AMP are brands and they make every other type of connector, I should really just try to use a name for them (I *hate* calling them just "4-pin" connectors). Is it generally accepted that these can be called "drive" or "standard" connectors and that the smaller ones can be called "floppy" or "accessory" connectors? That would make it simple:

24-pin ATX, [8-pin AUX/8-pin ATX +12v], [Floppy/Accessory], [Drive/Standard], SATA, and PEG.

Of course, I've seen video cards that use the "floppy" connector (Radeon AIW 9800 Pro) and the "drive" connector (like these XFX cards and early 6800 cards), but those sound like more commonly understood names than "Accessory" and "Drive" connectors and certainly more appropriate than "Molex connectors," which was stupidly accepted at one time (they are all "Molex" or "AMP" or another brand).

Originally posted by: John

Originally posted by: mpilchfamily
Wait a monute the video cards shouldn't be using the regular 4 pin molex connectors. The PSU will have 2 x 6 pin PCI-e connectors. Each of the 8800 GTSs will use one of those connectors. So you will have all 6 of the 4 pin Molex for your drives and fans. Do not try useing adapters for the PCI-e power connectors when the PSU will already have those connectors for you.

Originally posted by: CZroebut I am still using the same Molex/AMP-powered 7800GT video cards until the 8800GTS 640MB cards come under $300.

CZroe, if I were in your position I would also order 2 more modular sleeved molex cables from Antec so that you do not have to use adapters. I would also recommend selling the OCZ psu since your Neo is more than adequate for 8800GTS SLI + quad core.

It's actually NOT a very high wattage... it's only 500w Neo HE. The reason I said "higher wattage" was because it was new and I couldn't remember what my brother had bought exactly. Because I remembered that it was SLI certified, I assumed that it was a higher-wattage PSU, seeing as how the difference between similar OCZ PSUs earning SLi certification or not is 100w over 600w. I assumed that it was at least more than 500. I see 550w Neos all the time and I assumed that this was as low as they go.

 

[mpilchfamily]

The 7800s aren't all that power hungry. You can actualy use a single y-adapter and have both cards on one string of 4 pin molex. You will not be overloading that line nor will you be overloading a single rail. Just don't have any other components on that strng of connectors. The wires can easily handle the current that the 2 cards will be pulling through. Really that is you biggest concern.