All computers currently being deployed at CFHT are intel architecture, but we have a history which started in Hewlett-Packard (and some Sun Microsystems) workstations. Except for format (rack mountability versus a tower) the same machine can typically fill the role of Display Host, Session Host, and Detector Host well. This makes the individual machines (and the parts inside) act more as building blocks than hardware purchased for a specific task. While the extremely competitive PC market has some products with the wrong corners cut, properly engineered hardware is not so difficult to find. We opt out of most maintenance contracts and put the total saved toward buying complete redundant spares to cover potential failures. Many decades of this policy has proven that system failures (power supplies, hard drives, fans) are low enough that this is a cost effective approach.
To minimize failures that do occur, it helps to have an understanding of the factors which can affect critical machines adversely, especially those at the summit:
Approval for use at the high elevation of Mauna Kea (4200m) is not always easy to find, so we often are left to determine that one experimentally on our own. We have had consumer-grade PCs (serving functions not related to operations) at the Summit for years and experienced very few problems with them.