We often get asked if a motherboard or single-board computer (SBC) based system is the best solution for a particular application. Here are some things to consider when making the decision on your next order.
The SBC is a host card that plugs into a backplane. The backplane can support up to 20 slots of varying types, including PCI, PCI-X, PCIe, and sometimes even ISA slots. Motherboards commonly have a maximum slot count of 7. Even if you don’t require a large number of slots, you may have to go with the SBC if you need an unusual slot configuration like, one ISA and a PCIe x16. The SBC/backplane route may be your only option because motherboards are usually made to support the latest technology.
Variety of Supported Technology:
Motherboards offer a wider variety of newer supported technologies, i.e., slots, chipsets, I/O and processors. This provides a distinct advantage over SBCs which typically have a more conservative and slower development cycle.
SBC’s tend to have a longer product life cycle. Typically, motherboards have a short life cycle as manufacturers offer the consumer market the latest and greatest technology. However, at Chassis Plans, we have close relationships with embedded motherboard suppliers offering motherboards intended for industrial and military markets. These suppliers understand the need for long term revision controlled availability. This allows us to provide both SBC and motherboard based systems for with consistent availability of 5 years or more.
Motherboards provide the most current technology, while still offering long life options. These systems will be capable of handling faster and more intense computational processing requirements than the typical SBC option.
Card Slot Bandwidth:
A PICMG 1.3 SHB (SBC) provides a single PCI Express x16 port and an additional x4 port to the backplane. All the card slots multiplex through these ports to the processors on the SBC. A backplane providing eighteen x16 slots only offers a single x16 pipe to the processors. Motherboards are available providing four double-wide x16 slots providing true x16 bandwidth per slot to the chip sets and processors. This may be important in high bandwidth applications such as GPU servers where up to four GPU boards may be installed.
SBC-based systems have a lower mean time to repair (MTTR) because the repair only requires that you unplug and replace the bad SBC or peripheral card. If there is a failure on the motherboard, it requires disassembly of the system to repair or replace the motherboard. This can result in hours of lost productivity.
Motherboards have the advantage of costing less. Systems using single board computers are generally more expensive when compared to motherboards. If cost is a main part of the decision the motherboard may be the best solution.