asrock h61 BTC pro - not recognising more than 4 graphics card (6 installed)

[chqshaitan]

Hi Guys,I purchased a asrock htc b61 with the plan being to run 6 gfx cards on it.

I built the machine in two stages.

Stage 1

installed the bare bones components (processor, ram etc etc) then installed 3 graphics cards. All this is running from 1 x 1000w corsair platinum rated psu. left it mining for 24 hours as a burn in test and Everything was fine.

Stage 2

Installed the remaining 3 graphic cards, these are powered by their own 1000w corsair power supply, but for some reason 2 of the original cards installed in phase 1 are not working. I know the cards are fine as they ran for 24 hours without any issues.

General

As well as supplying power to the two molex connections, each gfx card riser is powered as well. I have a watt meter and the rig with 4 cards running (under mining load) and 2 not recognised, it is pulling around 1200 watt, so well within the capability of 2x 1000w cards.I am on the latest bios for the board, 1.20 and running windows 7 fully patched as the o/s.

Any ideas on what i can do to get the 2 cards properly recognised?I have raised this as a technical query but thought its worthwhile posting here so i can get other peoples experiences as well as document my own.

[parsec]

Re: asrock h61 BTC pro - not recognising more than 4 graphics card (6 installed)

So much hardware information is missing here:

The six video cards are what? All the same, a mix?

Graphics card riser is?

CPU being used?

Are the two PSU's connected in any way?

Did you clear the CMOS/BIOS after adding the additional cards in Stage 2?

Did you try going back to three cards (Stage 1) and are all three cards recognized?

Did you try adding one card at a time, clearing the BIOS after each new card is installed, until cards begin to disappear?