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H8QGL and EPS12V Splitters?

P

plext0r

[H]ard DCOTM x3
Joined
Dec 1, 2009
Messages
780
I received a SuperMicro 2U 2x1200W chassis from a forum member. It only has 2 EPS12V 8-pin connectors coming off the redundant power supplies, but my H8QGL motherboard requires three. I was thinking of using this chassis instead of the Blackhawk Ultra case once my board gets back from RMA.

1200W is plenty to power my 4P G34, but the lack of 8-pin connectors makes me wonder...

Since my motherboard requires 3 8-pin connectors for best power delivery, I was wondering how bad it would be to use on of these EPS12V Y-splitters?

EDIT: In doing some research, it appears each pair is good for 7A, so 28A for the 8-pin connector or 336W at 12V. I imagine I could even put a 4P 2011 board in this chassis and use two of the splitters since the X9 boards have 4 8-pin connectors. Thoughts?

12-198-019-Z02
 
Thoughts?
I hate splitters.
but if you have no pcie to adapt....
 
I'm thinking you risk melting the PSU cable due to very high currents. It depends on your overcloc,, really. I'm getting issues pulling 350w through each of my 8pin's using an AX1200. That is, I'm using 3 8 pin connectors, no adapters. If I did what you're doing I'd have 700w through one of them... I can SMELL the outcome already :p

I actually had a cable melt on me already, the connectors were fine, but the cable itself was... "crunchy".
 
Has anyone measured DC current going through the 8-pin connectors on the GL board while overclocked? I wonder if any of the 8-pin connectors run more amperage than others and I could position the 8-pin splitter accordingly.
 
I somehow doubt he is going to try and run at 4.3ghz.
but... I still hate splitters... for your listed reason.
 
Patriot said:
Thoughts?
I hate splitters.
but if you have no pcie to adapt....
Click to expand...

You don't know if there are any dual-pcie to 8pin eps adapters out there? Not sure how much I trust a single 6/8-pin -> 8pin EPS, as there are only 3 12v wires in a 6/8pin pcie cable.
 
knopflerbruce said:
I'm thinking you risk melting the PSU cable due to very high currents. It depends on your overcloc,, really. I'm getting issues pulling 350w through each of my 8pin's using an AX1200. That is, I'm using 3 8 pin connectors, no adapters. If I did what you're doing I'd have 700w through one of them... I can SMELL the outcome already :p

I actually had a cable melt on me already, the connectors were fine, but the cable itself was... "crunchy".
Click to expand...

Ouch, this is what I was afraid of. So how does SM sell this thing with only 2 8-pin connectors and claim it works with Gi motherboards, most of which also have 3 8-pin connectors? I found a couple of older Gi motherboards with only 2 8-pin connectors, but I imagine they stink for overclocking.
 
knopflerbruce said:
You don't know if there are any dual-pcie to 8pin eps adapters out there? Not sure how much I trust a single 6/8-pin -> 8pin EPS, as there are only 3 12v wires in a 6/8pin pcie cable.
Click to expand...

Adapters? Bah...just run 2 in backwards... its a little tight but it will fit. :D

IMG_20130507_003006.jpg
 
Last edited:
Patriot said:
I somehow doubt he is going to try and run at 4.3ghz.
but... I still hate splitters... for your listed reason.
Click to expand...

Nope, I'm trying to reach 3.5GHz again once my GL is back from RMA. Air-cooled.
 
brilong said:
Ouch, this is what I was afraid of. So how does SM sell this thing with only 2 8-pin connectors and claim it works with Gi motherboards, most of which also have 3 8-pin connectors? I found a couple of older Gi motherboards with only 2 8-pin connectors, but I imagine they stink for overclocking.
Click to expand...

Two things on this post:
1. The case you have originally came with an older H8QGi boards with the two EPS connectors, hence the power supply setup you have (I had two of these boards, including one that came from one of those cases.)

2. None of these board were designed to overclock

What other outputs do you have on that PSU? You may just have to run with two EPS plugs, which should work fine. Otherwise, you need an adapter of some sort.

Tear has really spoiled us rotten on overclocking 4P G34 boards... :p
 
Do not use splitters. Splitter == ensuring that board connector is the bottleneck (melting point).

I also recommend against mutilating connectors/cables by forcing PCI-E cables backwards.
Do not use Molex<->EPS adapters either (not enough current).

PCI-E<->EPS adapter is the most elegant solution to this problem that I know of.
 
musky said:
Two things on this post:
1. The case you have originally came with an older H8QGi boards with the two EPS connectors, hence the power supply setup you have (I had two of these boards, including one that came from one of those cases.)

2. None of these board were designed to overclock

What other outputs do you have on that PSU? You may just have to run with two EPS plugs, which should work fine. Otherwise, you need an adapter of some sort.

Tear has really spoiled us rotten on overclocking 4P G34 boards... :p
Click to expand...

Understood. Thanks for the history. I have another option. I believe the 4P 2011 systems pull less power overall, so what if I put the 4P 2011 setup in this case (even though it requires 4 8-pin connectors, each CPU pulls less wattage than the G34s so maybe I use two EPS12V splitters or solder some new 8-pin connectors onto the redundant power backplane).

I bought a SM 4U case from a different forum user and it has 4 8-pin connectors from the redundant 1400W power supplies. I think it better suites me to put my 4P G34 in this beast of a case and try the 4P 2011 in the 2U case. What do you guys think?
 
tear said:
Do not use splitters. Splitter == ensuring that board connector is the bottleneck (melting point).

I also recommend against mutilating connectors/cables by forcing PCI-E cables backwards.
Do not use Molex<->EPS adapters either (not enough current).

PCI-E<->EPS adapter is the most elegant solution to this problem that I know of.
Click to expand...

I thought that pcie solution was rather neat - if the wire thickness is the same as for the 8pin EPS cables, there's no obvious reason why it's not equal to using an 8pin EPS, no? I'd make sure they use the same 12v rail, though... if you're using a multi-rail PSU.

Maybe the board connector will melt first if it's the bottleneck, but I have a feeling that the cable insulation has a lower melting point than the plastic used for 8pin board connectors. I had one of my KGPE-D16's die due to fire on the 8pin connector (something was faulty, either the connector itself or the PSU cable), but the PSU cable had melted alot more than the board connector, which showed very few signs of changing state to liquid.

You seem to have alot of knowledge, what are the current/power specs of an 8pin EPS? I can't find this info anywhere. I know that ASUS M4A79XTD Evo has a 4-pin connector, and supports the 140w Phenom II 965. Then an 8pin connector should be spec'd for at least 280w.
 
I've decided to try soldering a couple more 8-pin connectors straight to the 12V connections shown here. These two 1200W power supplies are load-balanced.

 
Hmmm and who has proven that running only 2 - 8 pin connectors in either of the boards will not work. You definitely cannot prove that by me. I run 7 - 4P rigs at first I thought that I needed the 3rd 8 pin but guess what you do not on either the G34 or the 2011 I have successfully run both with 2 - 8 pin connectors up to 1180 Watts for quite a while on the G34's and a few Months on the 2011 platform with no damage to date. :eek:
 
Similarly here (though no higher than 920-930W) but I wouldn't make general "you'll be fine with two*"
recommendation (esp. if going after 3.4 GHz on IL chips). Better be safe than sorry**...

*) splitters don't count as they don't magically allow more current to flow through the common
&#8194;&#8194;connector/cable
**) imagine losing one or more +12V wires due to weak solder joint at the PSU -- remaining wires
&#8194;&#8194;&#8196;would then share the load of the lost ones == more current per wire == more heat == more risk;
&#8194;&#8194;&#8196;I have no way of proving it but I suspect that's what happened to rascal's machine

knopflerbruce, I wasn't thinking straight before, I didn't mean the board connector, I meant the common
connector of the EPS12V Y cable and the PSU<->Y cable.
 
Reverse PCI-e connector works, but make sure it's not loose otherwise the surface of contact between conductors is not adequate. Less surface of contact generate more heat on conductor leading to burning wires.
 
Run your fans 120vac. Big server boards dedicate a lot of amps to fan operations.

Plus, your board will run cooler, and you will use less total power assuming the same amount of airflow. AC > DC as far as motors go.
 
Qinsp said:
Run your fans 120vac. Big server boards dedicate a lot of amps to fan operations.

Plus, your board will run cooler, and you will use less total power assuming the same amount of airflow. AC > DC as far as motors go.
Click to expand...

That brings up an interesting point. Running the case fans on a dedicated 12V power supply if you don't care about PWM or noise could help the overall stability of the motherboard. All the fan power is not running through it so it would just be distributing power for the CPUs and other components.
 
I did burn an EPS splitter on my 2P board,the vendor repaced it by another splitter with better thermal insulation, that folded 24/7 half a year. Though, I bought a better PSU recently (Corsair AX 860 Platinum)

Slightly off topics but what about the PCI-e cables with splitters like 60 cm cable reaching 6+2 PCI-e, then splitted to 10 cm 6+2 PCI-e, that often come bundled with the PSU ?

For the ATX 860 you get bundled 2 cables with 2 x (6+2) PCI-e pin, and 2 cables with 6+2 PCI-e pin. Can I safely connect 8-pin and 6-pin of a GTX card to the same cable ?
 
From my troubles DO NOT use EPS Splitter. I did and basically killed a board, splitter burnt due to amperage then 3rd EPS melted as it was carrying full load of board. POOF. So now it only works with one CPU.:mad:

Tear is right about EPS splitters
 
I’m a bit paranoid about adding unnecessary connections, so if you have enough PCI-E connectors (12v lines) get receptacles and extractor tool and redo your connectors. PCI-E, EPS, 24-pin main and 4-pin CPU (P4) connectors use same terminals.

EPS housing

extractor tool
 
How did this work out for you?

i'll just post for anyone that searches on this topic in the future, but i'm using an older Super Micro SC748 chassis/case which came with the PDB-PT748-8824 power supply distributor... and it came with 4 EPS12v connectors, of which i use 3 with my H8QGi-f. The power supply modules that came with the SC828 and the SC748 seem similar in dimension, as well as connector so i wonder if the PDB-PT748-8824 power supply distributor could replace the stocker. This backplane also works with the very quiet PWS-1K41F-1R 1400w 80+ gold power supply modules as well (the original 1000w PSUs were crazy loud as the fans ran at full speed constantly).
 
I've repinned my pci-es to do eps. You can also trim them with a knife to allow them to fit. Do Do Do Do label your cables if you do mod or change them. I am not advocating you mod your cables, that is your call. I would do it. and have done it for a number of machines.

Smokey the bear will like it if you do not burn your California house down and start a forest fire.
 
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