InvalidError :
dgingeri :
Still only 40 lanes of PCIe? Grrr... I need 48, darnit. I need it to handle dual video cards, a raid controller and 10Gbe, and that takes 48 lanes.
There is no benefit to going beyond x8 on PCIe 3.0 for GPUs (almost none over x4 most of the time) so you can use 2x x8 for GPUs,
This is a very absolutist statement and is rooted very much in the current state of affairs, rather than looking towards 2014 and beyond.
The first exception I'd cite is that of partially-resident textures, where main memory is used to hold textures too large to fit on the video card. This puts much more strain on the bus.
Second, consider the fact that scene geometry continues to increase and the GPU is increasingly involved in tasks like physics and AI. Whenever the CPU and GPU are collaborating like that, it's not just the bandwidth that counts, but also the latency. The sooner the CPU gets the answer back from the GPU, the sooner it can start performing the next operation (and faster bus speeds reduce transmission time).
Finally, consider applications specifically involving GPU-compute. Depending on the application, the bus can quickly become a bottleneck.
If you look back through previous advances in bus architecture, you'll see that the first couple generations of games and graphics cards didn't benefit much from a new standard (I'll make an exception for AGP, which was long overdue). But well before the next generation comes along, products and applications have evolved to take advantage of the capacity of the previous generation.
Since both of the major new consoles have APUs with extremely high-bandwidth CPU <-> GPU communication, I suspect we're in for a wave of games thare are increasinlgy sensitive to GPU bus bandwidth.