8-Pin CPU connector headache!!

[PowerPie5000]

Ok my new Biostar TH67XE motherboard has an 8-pin CPU connector and my Cooler Master Silent Pro Gold (modular) PSU also has an 8-pin CPU connector (which splits into 2 x 4-pin connectors)... I'm currently running my rig with just one half of the 8-pin connector plugged in as the other half is keyed differently to the connector on the motherboard... But it still fits without forcing it. Is this normal?


This is the type of CPU connector on my PSU:






And this is the type of 8-pin connection on my motherboard (not a pic of my actual board):





... I'm confused! I dont want to fry anything!

[SUMMONER]

It's because on older motherboards (ie: Pentium 4) the 4pin P4/aux power connector design was reversed.

By using a plug like you show in the 1st picture the PSU can be used to power both the older and newer motherboards.

[PowerPie5000]

So i can't use all 8 pins? They all fit although 4 pins on one half of the PSU connector are semi-rounded (instead of 2 semi-rounded and 2 square).

The PSU manual states that it is ATX12V v 2.3 and EPS version 2.91 compliant... I'm pretty sure EPS uses all 8 pins and my motherboard has an 8-pin connecter, so why are they keyed differently? I'm almost sure the old 4-pin connectors didn't use 4 semi-rounded pins... But i could be wrong. My old P4 rig has 2 rounded and 2 square holes like in the picture you posted... Which is the same layout as half of my current 8-pin CPU connector. This is confusing!

[Hoonigan]

In my experience, if it's not supposed to fit, it doesn't.

Although, I'd wait for some more advice before plugging it in...

[PowerPie5000]

I looked in the motherboard manual and it seems even Biostar have made a mistake with their pinout description... How can you possibly plug a 4-pin connector into pins 1, 2, 5 and 6 with the way they've numbered the pins??? Surely this is a mistake? Even the pin assignments look iffy!

[PowerPie5000]

I've emailed Biostar about the mistake with their CPU connector pinout in the manual. I believe pins 1-4 should be +12V and pins 5-8 should be ground. They also have pins 5-8 labeled backwards!

In my experience, if it's not supposed to fit, it doesn't.

All 8 pins on the PSU connector fit perfectly into the 8-pin motherboard connector... despite one half of the PSU connector having 4 rounded pins instead of 2 square and 2 rounded.

Are there any differences between an ATX 4+4 pin connector and an EPS 8-pin connector? Apart from one being in two parts?

[Terbinator]

It will be good to see how Biostar react to this.

OTOH: Anyway you could return the board if need be?

[PowerPie5000]

It will be good to see how Biostar react to this.

OTOH: Anyway you could return the board if need be?

I won't need to return the board as there's nothing wrong with it, just an incorrectly labeled diagram in their manual (must have got lost in translation somwhere). I've heard that most Corsair PSU's also use the standard ATX 4+4 pin connector instead of the correctly keyed 8-pin EPS12V connector...And they say it still fits into a standard EPS12V motherboard connector. I've also emailed Cooler Master about this.

.. My brother's XFX PSU has a seperate 4+4 pin connector and 8-pin EPS12V connector (both keyed slightly differently but both still fit and work with his motherboards 8-pin connector).