fortiori I expect the PCH to be able to cope with a higher percentage of potential usage scenarios from its available ports than it can currently. It's simple math really:



Due to PCI overhead you get about 1800MBs max bandwidth divided between:



6 Sata III/1 M.2 ports at rough total of 3600MBs

6 USB 3 ports at roughly 3000MBs

8 USB 2 ports at a rough total of 240MBs

Integrated LAN at 100MBs



So here you have a paltry 1800MBs link trying to manage 6940MBs of potential bandwidth.



This isn't about I/O numbers, or more bandwidth for the sake of more. This is about smooth operation in high utilization scenarios using the ports integrated into the system. No matter how you slice it the bandwidth PCH bandwidth is woefully inadequate for the functionality provided and it should have been widened years ago to accommodate the faster and increasing number of interfaces (USB 3/SATA III) not to mention the introduction of SSDs.



I don't expect the PCH to do everything under the sun, I simply expect it to be able to cope perfectly fine with the bandwidth requirements of all its integrated (read: advertised and marketed) ports.

That problem with your logic is that according to your logic ALL I/O is used at the same time. This iswith consumers. It's rarely even true with servers either. It's an unrealistic use case.Tell me about how you have 6 SSDs running full-tilt constantly, and how you have 6 USB 3 ports (probably on two or three hubs, so it's actually half of what you think it is or less,) also running full tilt filled with... what? Hard drives? Flash Drives? USB 2.0 barely scratches the surface and neither does integrated LAN. So with that said, tell me more about how you have SSDs plugged into every SATA and USB 3.0 port running full tilt all the time. Let me tell you something, that's unrealistic.Additionally, DMI does not use PCI-E. It's similar, yes, but two different signaling technologies nonetheless.You also left out the 8 lanes that the PCH tends to offer which takes a bite out of DMI's bandwidth. If nothing is happening, you'll always have enough bandwidth regardless of how many devices are plugged in.With that all said, you would need to doto hit that limitation and if you are hitting I/O that hard and if it becomes a problem, it's still an argument for you to get a RAID controller and stop relying on the PCH. To think that your "integrated option" is the best answer for everything is ludicrous. I don't see gamers running around with Intel IGPs saying that it's awesome for gaming and you don't see sysadmins running around claiming that the PCH/MCH/South Bridge is the best option for I/O. Much like how anyone who actually has experience with a RAID controller knows that the benefit can vastly outweigh the costsSo it's actually not just "simple math". That would be true if everything was running full steam ahead, but it doesn't work that way. Also I would gladly give up 10% of my performance across the board to run that much hardware at full tilt. I don't think you realize how powerful the PCH really is. This tends to be a common problem when people complain about something they've never encountered then try to claim they know something about it. Stick with what you know, please.Until you can show me that you've reached this limit without doing anything too extreme (something that less than 1% of consumers would do,) I think you're arguing about something that doesn't actually matter. Can you saturate DMI? Sure... but what does it take to do it? The answer is: More than you'll ever should do with the PCH anyways or probably even with your tower in the first place.Additionally, considering the nature of each bus. If everything was reading AND writing the same amount at full tilt (not just reading or just writing), DMI 2.0 actually has almost enough bandwidth to drive everything at full speed considering DMI 2.0 is 20Gbps bi-directional (40Gbps total).Most people don't even have two SSDs, forget 6. Most people don't fill up all of their USB 3.0 ports with high-bandwidth devices either. Lets stick to reality.