A computer system is presented which implements a system and method for tracking the progress of posted write transactions. In one embodiment, the computer system includes a processing subsystem and an input/output (I/O) subsystem. The processing subsystem includes multiple processing nodes interconnected via coherent communication links. Each processing node may include a processor preferably executing software instructions. The I/O subsystem includes one or more I/O nodes. Each I/O node may embody one or more I/O functions (e.g., modem, sound card, etc.). The multiple processing nodes may include a first processing node and a second processing node, wherein the first processing node includes a host bridge, and wherein a memory is coupled to the second processing node. An I/O node may generate a non-coherent write transaction to store data within the second processing node's memory, wherein the non-coherent write transaction is a posted write transaction. The I/O node may dispatch the non-coherent write transaction directed to the host bridge. The host bridge may respond to the non-coherent write transaction by translating the non-coherent write transaction to a coherent write transaction, and dispatching the coherent write transaction to the second processing node. The second processing node may respond to the coherent write transaction by dispatching a target done response directed to the host bridge.