>> What about the X5000's x4 slot (the one behind the PCIe-PCIe bridge)? Wouldn't a
>> normal PCIe x16 card work in it? [...] Wouldn't a SATA3 card work full-speed in it,
>> even if it was somehow limited to x2 speed by the bridge bottleneck?

> X5000's x4 slot is blocked by any video card wider than single slot.

So what? Single-slot graphics cards supported by OS4 are widely available, so this doesn't render my questions invalid.