Balanced Technology Extended (BTX) Interface
Motherboard Size and Mounting Hole Placement
A BTX board must adhere to the mechanical details depicted in Figure 3-1. All boards must be 266.70 mm deep. The board width may range from 203.20 mm to 325.12 mm as per the following table. The following table lists typical board sizes and the mounting holes required for the motherboard. A BTX chassis must provide mounting points and add-in card apertures in the rear panel for the largest board that it is intended to support.
Table 3-2. Board Size Options
Board Designation | Maximum Board Width | Maximum Number of Add-in Card Slots Available | Required Mounting Hole Locations | Notes |
picoBTX | 203.20 mm | 1 | A, B, C, D | |
nanoBTX | 223.52 mm | 2 | A, B, C, D | |
microBTX | 264.16 mm | 4 | A, B, C, D, E, F, G | |
BTX | 325.12 mm | 7 | A, B, C, D, E, F,G, H, J, K |