Originally Posted by CynicalUnicorn
The only time a dual-GPU is better than a single-GPU is for mITX. You can only fit a single Titan/780, but you can fit two 680s/7970s using a 690/7990. Otherwise, crossfire/SLI is better, mostly for heat, but also partially for additional PCIe bandwidth.
Not sure why you're referring to PCIe bandwidth when discussing single GPU cards vs crossfire. In the case of the 7990 for example, the 7990 is actually MORE efficient than 7970s in CF, and performs better, which nulls your statement about there being 'more' bandwidth available. There is actually less, and FAR more latency over PCIe than a dual gpu card would have locally over the PCB. The signal has to travel a much farther distance. Not only that, but we are not limited by PCIe bandwidth at all with the current GPUs. Even PCIe 2.0 8x does not incur a significant performance penalty when running even a GTX Titan, for example.