The front side bus used to be the main highway to the rest of the peripherals but these days basically just connects the CPU to the memory. It's been superseded by a DMI bus to the northbridge these days since the FSB can't keep up.
That shows how long ago I did my degree in computer science; nearly 20 years ago now. AGP, FSB, its all different now
![Confused :?](./images/smilies/icon/confused.gif)
DMI, Northbridge; I am going to have to do some Googling.
If you remember rightly, I already have an X99 mobo with a V3; but a single CPU like we know only offers the dedicated 40 lanes, so no true 5 full speed GPU slots on this.
I think the best would be dual Xeons, as at least that will give 40+40 lanes, which 5*16 obviously equates to the same number. I prefer the V3's as they use substantially less TDP than the V1's, plus you get the DDR4 ram, and AVX2.
I have found some Supermicro mobos that seem to offer what I need, but not as E-ATX, but their silly proprietary form factor size; perhaps the way forward is to get one of these mobos, and order a sheet of plastic (as used on the existing GPU Rack), and just drill the holes in the correct place. Although if I remember rightly you have use a special drill attachment to put the screw threads in. I am no expert in this though.
The main reason for wanting full speed etc, is to future proof the rack. As we know every N months/years new GPUs come out which pump more data through the PCIE bus, plus no doubt you will get some future projects using more CPU cores, or perhaps SLI etc, and hence keeping the full dedicated speeds/sizes if possible I think would be best.
I do not mind the 970's running at x8 speed but really I want anything above to be at x16, full width, gen3. Although all of this logic may be undone if PCIE 4/5 gets released anytime soon.