Does anyone know if it's possible to buy an adaptor cable which plugs into a motherboard's PCIe x16 slot, which then has 16 PCIe x1 slots attached to it, one PCIe lane each? I was wondering if it might work out cheaper if in addition to my expensive gas boiler I was to heat my house by Litecoin mining. Almost all the power used by the GPUs is lost as heat, but in winter heat is something I want and something I would have to pay for anyway. This would in effect be a noisy and bulky fan heater which generated both heat and money, the heat would make up for the fact that LTC mining uses a bit more electricity than the value of the LTC it mines.
Every calorie of heat the mining machine blows out is a calorie my boiler doesn't have to produce. Obviously there's the component costs too, those would have to be second hand, such as old HD5870s which work fairly well but aren't very expensive any more.
Maybe I could find a way to create such a cable if they're not commercially available
Do you mean like this?
http://compare.ebay.com/like/190859065774?var=lv<yp=AllFixedPriceItemTypes&var=sbarWhat would the purpose be [I mean, its making heat either way?]
Your boiler is more efficient as a heater than some GPUs.
Similar to that cable, but to plug into a motherboard's PCIe x16 slot at one end, and split into 16 cables with one PCIe x1 adaptor on each of the other ends to connect to 16 graphics cards. The amount of data needed by each card mining can easily be sent through a single PCIe lane, after all the BFL 7GH/s vapourware miner that I've had on order forever uses a USB lead which is even slower. (Where's my damned ASIC then, BFL?)
As for efficiency, consider it like any other machine for a moment, forget about data because that's not quantifiable in this way. The card uses a certain amount of power, say 250W perhaps. now where does all that power go? The amount of electricity used by the PCIe interface is very small, the same goes for the video output cable. This means that the bulk of the power is going somewhere else. There are only three other ways for the power to go, remember that energy can neither be created nor destroyed, it has to go somewhere. Those three ways are heat, noise and into kinetic energy from the fan and the air that it moves. The moving air and the spinning fan will lose their energy as heat from friction in the bearings and against the air in the room, there's no other place for it to go but that's only a small proportion of the energy that the card uses anyway. The noise isn't like a stereo turned right up (for a single card anyway!) so that can't be using a lot of energy either, and the sound vibrations in the air will also convert into a small amount of heat as the atmosphere in the room or the bricks in the wall absorb them. This means that almost all the energy goes directly into the heat lost from the GPU itself. Even the electrical signals absorbed in the motherboard and the monitor will eventually be lost as heat too. So this effectively means that all the energy that goes into the card becomes heat from one source or another, the only lost energy is from any sound which escapes the building and loses its energy outdoors, which will be negligible.
So, given that virtually all the power used by the card must become heat inside the room, that means that it would produce exactly the same amount of heat as an electric fan heater that used the same amount of power, so it would cost the same amount of money to run it. The fact that whilst it's heating the room it also generates Litecoin is bonus, and when that's counted against the electricity bill it means that a mining rig is a cheaper way to heat a room than an electric heater is. Of course though this still leaves the cost of the equipment, which is the only thing which can make it work out more expensive overall, that's why getting the parts cheaply is vital.
Anyway, I like tinkering with electronics so it's something to occupy me during those long winter nights.
Of course though there's still the issue of whether the noise will drive me insane!