I think I have things running at a stable 70 GH/s for two boards now. It took a bit of stopping and restarting, and I ended up switching from BTC Guild to EclipseMC, but both the web interface and the pool say I've been mining at a bit over 70 GH/s for several hours now.
Last night, I pulled out the D945GNT and the GPUs and added a power adapter cable and a USB hub. The "adapter cable" is a 24-pin ATX extension modified as follows:
1. Tie PS_ON to GND so the power supply stays on as long as it's plugged in (mine has a hard switch on it that can be used to shut it off).
2. Bring out the two +12V pins (and GND) to a pair of 2.5mm barrel plugs for my Jalapeños.
I might add a smaller barrel connector on one of the +5V lines to power the USB hub; that'd allow me to get rid of the wall wart that was included with the hub.
This is what I currently have running:
- v3 M-board with two v2.2 H-boards and a Raspberry Pi model B (version numbers are IIRC)
- Seasonic SSR-550RM power supply (was originally purchased for GPU mining)
- Cooler Master JetFlo 120 fan (maxes out at 95 cfm @ 2000 rpm, but I have it connected through an (included) adapter that knocks the speed back to 1600 rpm as full speed may have been cooling it too much)
- a powered USB hub
- Coldtears 2.8" USB LCD
- two BFL Jalapeños
- D-Link DAP-1522 wireless bridge
The Kill-a-Watt says all this is pulling about 140W at 80 GH/s. The motherboard-and-GPUs combo was pulling another 300W or so for about 450 kH/s of scrypt mining. Even with Novacoin mining being worth 10x the equivalent Bitcoin mining, 300W for ~4.5 GH/s equivalent is a bit much...the Jalapeños do that with a tenth of the power. I could probably knock a few watts off that by replacing the wireless bridge with either a USB WiFi dongle or a proper wired network connection, and by running the hub off of the power supply. I'd like to put the Bitfury rig in one of the Spotswood cases...waiting for the $ to arrive from CampBX.
I have a bunch of RAM heatsinks on the way...will probably be a week or two before they arrive. When they do, what's the best way to install them? Some pictures show them applied to the component side, but most seem to have them on the other side. I know there are a bunch of thermal vias under each chip, which would seem to indicate that placing the heatsinks on the back of the board would possibly be more effective at getting heat away from the chips. Are the thermal vias tented or exposed, though? I've not tried looking at them through a magnifying glass yet, and my near vision apparently isn't what it once was (now get off my lawn!). If exposed, heatsinks on the back would definitely be the way to go, right? If tented, it's not so obvious which would be better.