The SLI Bridge Connector
Without the properly fitting bridge connector linking the two cards together, only limited SLI operation is possible. With SLI bridge boards, the space between the cards is specified. As all motherboard makers use different spacings between the x16 slots on their motherboards, the manufacturers provide the bridge included with the product. We got two adjustable bridges from NVIDIA that can bridge any conceivable span.
Overview of the various different SLI bridges
Without the SLI connector attached, the driver gets grumpy. SLI works, but in a limited fashion (see Performance Analysis).