I'm not talking about theortectical thought exercises. I'm talking about dealing with real engineering problems with the components you actually have to work with.
If you have a CPU package with a 38 PCI-e lanes coning in each with 2Gbps of bandwidth then you cannot connect 200Gpbs of bandwidth to that box and expect performance. The transmission speed of the material connected to the outside of the box has zero impact on improving the internal bandwidth of the box.
Light Peaks controller/router puts the external singals onto the same internal electronic based buses/networks that the rest of the components are hooked to.
It does make more sense to transmit >5Gbps data over optical externally over relatively longer distances (as opposed to that betweeen CPU and GPU ). There is all kinds of problems that introduces that want to avoid. However, internally over relatively short distances neither Intel nor AMD (or any other high end CPU implementer) is giving up on electronic connection for the next several years. Interconnect between boxes ... yes that is going fiber ... Interconnect between boards (already done in high end mainframes IBM just dropped). However, that is because aggregating traffic between many CPUs/GPUs and transporting over a general service interconnect. Aggregating several slower speed data streams creates a bigger one to transport. that says and does nothing to improve the internal speeds of the sources/targets that network transports to.
Likewise 10Gbps is good at hiding the latency if increase the distances. So can put a PCI-e expander box outside the the box with a LP connector with a bridge chip in it. You connect the bridge to the internal PCI-e network with LP. That does not increase bandwidth. Having 18 PCI-e slots arranged in a tiered network doesn't not increase the total bandwidth inside the box. It means can have higher number of slower connections (that do not use all of the bandwidth on a PCI-e lane), not faster ones.
So for example could have LP from a iMac out to a external PCI-e expander box. That will not solve the problem of hooking the lastest 16x PCI-e v2 card to your iMac. You could stick in some 2x, 1x cards but any high bandwidth card will run right into the bottlenck wall. LP doesn't do jack to solve that.
Last edited:
