We are using a group of 8 Stratix V DSP boards in a data capture research project. These are all to be fitted into an 8 slot PCIe backplane. However we have encountered a problem, the heatsink fan is too wide. Basically we were hoping that removing the LCD would be sufficient to make these dev boards sit in adjacent slots, so that we could pack 8 into the backplane. However even after removing the LCD the fans are about a millimetre too wide for the cards to sit next to each other. Has anyone come across a cooling solution (fan, heatpipe, watercooling, whatever) that will mount in place of the fan on these board (55mm mounting centres) that will be low profile enough to allow the cards to sit back to back? I don't imagine that these boards require a high performance cooler, especially when considering the stock heatsink is loosely attached with plastic clips and no thermal interface material whatsoever - i.e. the heatsinks are probably doing very little to cool the FPGA! Thanks.