Datacenter workloads demand high computational capabili-ties, flexibility, power efficiency, and low cost. It is challenging to improve all of these factors simultaneously. To advance dat-acenter capabilities beyond what commodity server designs can provide, we have designed and built a composable, recon-figurable fabric to accelerate portions of large-scale software services. Each instantiation of the fabric consists of a 6x8 2-D torus of high-end Stratix V FPGAs embedded into a half-rack of 48 machines. One FPGA is placed into each server, acces-sible through PCIe, and wired directly to other FPGAs with pairs of 10 Gb SAS cables. In this paper, we describe a medium-scale deployment of this fabric on a bed of 1,632 servers, and measure its...