Topic: [ANN] US/North American Bitfury sales NEW STOCK ***NOW SHIPPING*** - page 35. (Read 576772 times)

Hmm, yeah they can be finicky/flaky, but I'm wondering did you make sure the cards are not wobbling? If they are left freestanding in the slots and you got a powerful fan blowing on them they will sway and wobble like crazy and this can cause them to work themselves loose from their respective slots. If you don't have a case for them I suggest maybe securing them by some method. Some have even used tape on the top of the cards. Also pay close attention to the slot arrangement. Make sure you have the cards distributed as evenly as possible across the various banks. Place the worst performing card at the end of the card chain.

None of my units run properly. I've tried everything, but the cards just drop offline if they show up in the first place. Then slots start going dead entirely and cards never show up on them again. I thought maybe I had a bad component. I just got two new 100gh units today, that I bought specifically to get my October unit working finally. These ones are just doing the same thing, so there goes that plan. They don't even run for 2 minutes without dropping cards. I've lost so much time and money and these things it's disgusting.  I've averaged about 50gh on my october unit, and I'm talking about 15 cards not 1.

So still no word on any possible price reductions?

*kicks Daves desk* Hey! Wake up! You got orders waiting to be shipped!

Yes

So one last question. It should be safe to have the two PCI Plugged in on the Front of my V3 Board, and 2 More going to the Back of the board on the Terminals from the same PSU of course.

That threaded rod with spacers between the cards is working well to stabilize them so they don't drop offline.

They are just for looks and don't actually want to sell them.

(Sorry couldn't help myself)

Why is the price so dam high for 400GH?

No, each splice has three 18 gauge wires (with extra thick insulation) from the PCIe plug on one end and one 12 gauge wire on the other end.

Don't you lose most of the benefit of distributing the load across many more wires if you don't use all 6 wires from each PCIe connector?  Your photo looks like you're only using one + and one GND from the PCIe connector.

I have 4 ring terminals on each screw. I'm using 4 of these for a rig:

So you just made me realize I need to buy two of those Extenders. Is it ok to connect two ring connectors to each terminal like that? At least that's the only way I see connecting for pci connections.

There's another reason to use more than 2 cables: reducing the power bill.

Let's assume the wires from the PSU to the rig are 18 gauge and 2 ft long, and the rig uses 600W. With two cables (don't use a single cable with two plugs!), we have 6 wires for each of + and -, each carrying 8.3A of current. Each of those 12 wires has a resistance of 0.0128 ohms*, so the voltage drop at 8.3A is 0.106V and the wasted power is 0.88W per wire, for a total waste of 10.6W. If you figure on running these rigs for 6 months and your power cost is $0.15/kwh (mine's twice that), you waste $6.95 just to heat the wires. The connectors probably add significant resistance and therefore waste even more power.

Now let's run the numbers for 4 cables instead of 2. 24 wires, 0.0128 ohms, 4.15A, 0.053V, 0.22W/wire, 5.3W total wasted on heating the wires. As a general rule, doubling the number of wires (or their cross-section area, i.e. 15 gauge vs 18 gauge) sharing the same load halves the power wasted. You save at least $3.47 over 6 months and reduce the risk of fire due to overloaded connectors.

Since my power costs twice as much as the examples above, I went a little overkill and made cables with one 12 gauge wire instead of three 18 gauge wires, for my modular PSUs, with male PCIe plugs on one end to fit the PSU and ring terminals on the other, for a total of eight 12 gauge wires (four +, four -) per rig.

* http://en.wikipedia.org/wiki/American_wire_gauge

I always adjust voltage (either with a pencil on the older boards or with the trimpot on newer ones) while powered but not hashing. It might be a bad idea, but it hasn't caused me any problems.

Ok, so I borrowed a volt meter from a friend to reduce the overclocking on my rig, but I have a question for those that have made adjustments (this is a v3 rig, so has the v2.2 H-boards).

Do you adjust the trimpot while the rig is powered up but not mining?  Or do you power everything down, make an guess at how far to adjust the trimpot, then power it back on to measure and see if you guessed right, and then repeat?

The concern isn't getting enough power to the rig, it's avoiding overheating of the connectors, since they weren't designed for 320W+ on a single cable.

I snapped a quick shot of a V3 M-board.  (Be gentle on my photoshop skills - I had a couple minutes to snap a photo while the relatives are cooking in the other room) You'll see the PCI-E plugs on the left, and the screwdowns on the right.  The V2 has technically the same layout.  V1 is screwdown only.

From what I have been told, you can plug into either/or.  Some people have both plugged in, but either should pull enough power from the PSU.

Some of the (I believe newer) V3 boards (there are more than one type of V3 m-board) have the screw down posts as well as pcie power connectors.  The one I have has those loose pci-e H-Card slots people where complaining about that result in flapping cards.  The other one is missing the posts, but the pci-e slots are stiffer.

Note:  I am not talking about the V1 or V2 that have the short ISA-like card slot

That looks easy enough, thank you Keefe