If I were to purchase a motherboard with 7 pci-ex ports. Could I then attach 7 graphic cards and run 7 cgminer processes? One for each card?

Or would a better build be to group cards together with SLI/Crossfire?

If one of these cards generally gives 1200mhash, would i be correct to assume that 7 would give me 8400? Or is there some overhead issue here I'm not aware of?

  • don't do it.. not worth it. Get a Block Erupter 333MH USB stick if you want to play miner. Even those are not worth the investment anymore, but at least you're not wasting 3000W of power.
    – Jannes
    Nov 15, 2013 at 13:34
  • this is a setup for litecoin mining, not bitcoin.
    – netbrain
    Nov 15, 2013 at 17:09
  • Well, perhaps you want to mention that in your question then. ;)
    – Murch
    Nov 22, 2013 at 2:49
  • And you shouldn't assume so much :)
    – netbrain
    Mar 5, 2014 at 19:09

1 Answer 1


A single instance of cgminer handles multiple GPUs, so there is no need to run separate processes. Enabling SLI(You aren't using NVIDIA cards, right...) or Crossfire will decrease mining performance, so leave it off.

There is no overhead associated with running multiple GPUs on a single system, unless the cards are physically spaced so close together that they overheat and throttle. 7 1.2 Mh/s cards would be expected to produce 8.4 Mh/s total.

At this point, investing in new GPUs for mining is questionable, and you should only consider GPU mining for scrypt-based altcoins such as Litecoin, as ASICs have made GPUs unviable for bitcoin mining.

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