In the scientific computing community, servers with GPUs are pretty common, and available off-the-shelf. See for example http://www.supermicro.com/products/nfo/

In the scientific computing community, servers with GPUs are pretty common, and available off-the-shelf. See for example http://www.supermicro.com/products/nfo/gpu.cfm http://www.supermicro.com/products/nfo/gpu.cfm So asking the folks that already use that stuff could give pretty accurate predictions.