Results: General-Purpose GPU
Netstor's TurboBox NA255A is intended for multi-GPU workstations able to leverage the compute power of graphics hardware. So, we start our evaluation using LuxMark.
As you can see, there is no difference in performance between a motherboard operating a PCI Express 2.0 signaling, a motherboard at PCI Express 3.0, and the TurboBox. This workload fully utilizes each graphics card's compute resources, but it doesn't tax PCI Express bandwidth. Consequently, scaling is pretty much amazing.
Again, we see nearly identical results between the motherboard-based cards and Netstor's TurboBox. This means that we don't have any trouble going outside of the box or stepping down to PCI Express 2.0, at least in compute-bound workloads.
On a related note, we ran the same bitcoin mining test on a Socket FM1 motherboard using a PCI Express slot limited to four lanes of connectivity. The result was identical to our 16-lane tests, around 550 Mhash/second. In other words, we're not worried about one third-gen PCIe x16 slot serving up enough throughput for a fourth card in Netstor's NA255A TurboBox. We hypothesize that there's still headroom available.