The MSI H81M-E33 uses the Intel LGA 1150 CPU socket. Any compatible Intel CPU will have the same socket entry. It uses the DDR3 memory type, with maximum speeds of up to 1600 MHz, and 2 DDR3 slots allowing for a maximum total of 16 GB RAM. 

Conforming to the ATX standard, the MSI H81M-E33 should fit into the majority of cases. ATX is the most common form factor, and as such has a high degree of compatibility with other components while providing a decent number of slots to widen your expansion options. 

The MSI H81M-E33 does not support onboard graphics. Any system build that uses this motherboard therefore requires a separate graphics card, or a processor that has a GPU on the same die, such as AMD APU processors. There are 0 PCIe x16 slots on this motherboard. The MSI H81M-E33 does not support multiple graphics cards via Nvidia SLI or AMD Crossfire.