19 minutes ago, manateeman77 said:
I'm not very experienced with what this means, but I just see smaller numbers than the Tomahawk has, so I got a little concerned.
The numbers tell you how many PCIe slots the board has, how many PCIe lanes are available on each slot and which PCIe generation it supports. Both the generation and number of lanes determines the maximum transfer speed of that slot. In practice, the number of PCIe lanes and the PCIe generation has very little impact on the performance of your GPU:
Both the Mortar and Tomahawk have one PCIe 3.0 slot with 16 lanes, which is what you'd typically attach the GPU to, so there shouldn't be any difference. They have a different number of additional slots and some of those slots will either be unavailable or have reduced speed if e.g. you attach an M.2 SSD. This shouldn't matter as long as you're not planning on using those slots for e.g. additional storage.