mining rig rack power upgrade

I recently got in enough parts to build 2 small 3x 7870 rigs (actually one card is a 7950). I needed at least 1 more power outlet because my first rig (5x 7970) was pulling 1200W on a nearby outlet, but I wanted to get a dedicated one for the first rig also.

My "rig rack" (built from the corner posts of an old server cabinet) had room for quite a few more motherboards so I decide to do a full bore power upgrade for future mining rigs.

Multi GPU Machines and PCIE In-Band vs. Out-of-Band Presence Detection

TLDR: 
To improve PCIE bus initialization during boot when trying to run x16 GPUs via various PCIE risers, short pin A1 to B17 on ALL PCIE x1 risers (in the unlikely event you are using x4/x8 to x16 risers, look up the proper x4/x8 PRSNT#2 pin and short that one to A1 instead).

I guess I should preface everything below by saying, I'd be happy to hear how PCIE bus initialization really works (in relation to the problem described below) from someone who knows PCIE buses.

Full Story

Last night I had a problem getting multiple Radeon 7970 GPUs running in a single motherboard, 4 cards good --> 5 cards pure chaos, lspci showing 3 cards only, swapping slots, risers, cards all showed that everything was good, just not in any combination over 4 and in fact, some combinations of 4 no good. (Maybe even some with 3).

7970 GPUs

Custom Arduino Shield for Android DRO Project

Here's a PCB layout for an Arduino shield customized for the iGaging Arduino interface Yuriy designed for his Android DRO project:

AndoridDRO_Shield_v0.1.pcb



It's (only) readable with software from ExpressPCB