My view of a good motherboard should have 7 PCI Express x8 lanes. That would require 56 lanes to provide 100% coverage. Dynamic lane allocation would be able to reallocate lanes when say a video card uses 2 slots. This would reduce the number of lanes needed at the expense of more complexity.
Installing a Wi-Fi card needs 1 lane so the remaining 7 can be allocated elsewhere such as for a M.2 card or two which need 4 lanes per card.
PCI Express crossbar switches in 36×36 full mesh are readily available. It’s probably necessary to use a pair of switches and use them in tandem to handle the lanes. The crossbar is mostly needed for slots under the video card that may not be in use.
Disk controllers may need 2 lanes for some low cost 8 SATA port cards. The 16 port SATA cards tend to want 8 lanes as most were designed for PCI Express 1.1 speeds. More expensive controllers may be able to leverage PCI Express 2.0 or PCI Express 3.0 speeds. Even x4 slots give a lot more potential for select peripherals.
PCI Express 4.0 is now coming to the consumer market which will double the bandwidth per lane. It will take time for new consumer peripherals to be designed for the new higher bandwidth. Generally legacy hardware is backwards compatible so existing consumer hardware will work fine.
MID BOARD USB
The Fenvi 802.11ac with the Intel 9260 Wi-Fi card needs a midboard USB 2.0 to support Bluetooth. The AX860i needs midboard USB 2.0 to support managing the power. The front panel box with a USB 2.0 flash card reader and USB 3.0 ports which includes a USB type C connector.
In total, 3 midboard USB 2.0 headers are needed and 2 midboard USB 3.0 headers for the hardware I use at present. Given modern chipsets lack enough USB 2.0 headers the best solution is to use a low cost USB hub mounted on the motherboard which could afford a double row of USB 2.0 headers for peripherals.
Many motherboards still have headers for RS-232 and Centronics printer ports. USB to RS-232 and USB to Centronics are readily available. PCI Express versions of RS-232 and LPT ports are also readily available. No need for motherboard headers.
Low cost USB 3.0 cards are popular for those with multiple mobile devices. The first gen cards offered 2 USB 3.0 ports but more recent cards now offer several ports. USB 3.0 uses more power than the slot can provide which requires a user to attach power from the PSU.
A basic desktop chassis may have one or 2 USB ports but front panel boxes with more ports are low cost and are available in many formats. We use a box with mixed USB type A and type C so that we can use the latest iPad Pro which uses that instead of the Apple Lightning cable with iTunes.
USB 3.0 cards with dual internal 19-pin connectors are popular for using multiple front panel devices. USB 3.0 cards with 19-pin and rear USB 3.0 ports are another option. USB 3.0 cards with SATA are more expensive.
There are still some contemporary ATX motherboards with PCI slots for customers who may have some old PCI card they want to use. Generally more than 99% of the functions of PCI cards have migrated to PCI Express.
The MSI B350 ATX motherboards tended to offer some PCI slots while the B450 ATX motherboards offer only PCI Express slots. Some models have dual M.2 slots but the second slot disables 4 PCIe slots negating the advantages. PCI Express x16 card with 4 M.2 cards are sold for high end users who may want to use 4 of the Samsung 2TB SSD drives.
The MSI AM4 B450 Gaming motherboards has 2 PCI Express x16 slots and 4 PCI Express x1 slots so that large numbers of devices can be installed depending on the customers needs.
The R5 2400G has integrated graphics so it has 8 lanes for graphics. The southbridge handles the secondary slots and it provides SATA and other interfaces.
We have long used wireless networking as it makes it far easier to cut down on cabling. At present the Intel 9260 is the flagship and Fenvi makes a PCI Express x1 card with it for those who use desktop machines. This provides 802.11ac wave 2 compatability and support for fat 160 MHz channels.
It may be a while before the 802.11ax hardware matures into 2020 so the existing Intel 9260 will likely see service for at least another 16-24 months. The Intel 9260 is 2T2R so it is already very good at connecting with distant infrastructure. WiFi is designed for up to 1500 meters outside and maybe 100 meters indoors.
The RTL8111 USB adapter works better with the access point in the same room. The 2T2R card works best with access points in adjoining rooms or attic mounted.
PCIe IEEE 1394a
We still use our old ZR10 mini DV camera, mostly for importing video via the IEEE 1394s cable. The camera in VCR mode is frame accurate and imported AVI files are 28 or 29 megabit in bandwidth which is closer to full 1080p HD BD than NTSC. VHS by comparison is around 3 megabit which is 1/10 as good as the ZR10, DVD maximum is 9 megabit and BD maximum is 54 megabit.
The MiniDV has been used for HDTV and HDV cameras support 1280x720p and 1920x1080i are available. The same 60 minute tapes are compatible. Not many cameras were available.
Beware that some people who have experimented with IEEE 1394b have discovered compatability problems. Consumer hardware universally uses IEEE 1394a which works perfectly in our experience. USB 2.0 with its higher bandwidth and low licensing costs drove IEEE 1394 into extinction. There are IEEE 1394a cards with an internal connector to support front panel headers.
Most IEEE 1394b cards have a 4-pin 1394a connector in addition to dual 6-pin 1394b connectors. Most IEEE 1394a cards have 6-pin connectors with possibly a single 4-pin connector. 4-pin cables tend to be fragile so its advisable to have several if a lot of content is being imported.
Years ago with 32-bit Windows and poor performing hard disks it was hard to handle video with such extreme bandwidth. This area was the biggest reason we adopted Windows XP x64 the day it was released.
Windows 8 and above need to download the legacy 1393 bus drivers. Save the installer as sometime Windows updates reset the driver. This way you can keep your old tapes handy for storing video safely in a box. Given everyone is using 64-bit Windows it makes more sense with video and extreme capacity hard disks. Video capture software generally loads streams into memory so the better memory management of 64-bit Windows makes perfect sense.
Our old Acer Q6600 box has IEEE 1394 but PCI Express cards are low cost if needed. The ZR10 can also record analog video from another source so it can import anything to the tape which has 60 minutes of capacity. With a 2TB hard disk, the machine can handle importing hundreds of MiniDV tapes before it reaches its capacity limit.
We have seen some mini DV cameras with USB 1.1 but this does not have enough bandwidth for handling the format. Imported video tends to be 1/4 frame 320×240. The high bandwidth IEEE 1394s imports the video at full frame and the software packs it into AVI files which are easily used with any compositor.
MiniDV cameras have more than enough bandwidth so the new HDV format supports 720p and 1080i resolutions while still using the existing miniDV tape format.
D5 is better with 350 megabit bandwidth, but the decks are $100,000 and tapes are $200 each, PCI Express controllers are over $2000. Typically D5 is rack mounted in a rack with a studio edit bay nearby. Such hardware setups can cost upwards of $1 million and are generally seen with television studios.
Digital8 cameras can play 8mm and Hi8 format analog tapes in addition to the native digital 8 format. These can imported by IEEE 1394 into AVI files for editing easily.
Professional NLE packages like Avid Media Composer can work with pretty much anything and with modern 4K video from mobile phones can be edited too. SSD bandwidth is so fast that it can cope with 12 tapes being feed into an edit for printing to a hard disk. Modern 4TB hard disks are fast enough for 8K video editing.
The iPhone 7 plus 128GB camera can shoot 4K30 clips. The camera uses the MOV format which is Apple’s video container. The CODEC is H.264 so the video can be posted to social media unedited.
Avid Media Composer can work with pretty much any format as novices try to learn how the professional tools work.
The Intel 9260 provides Bluetooth 5 support so it can pair up with any mobile device easily. Windows can notice when the phone walks off to go to sleep.