There are times when the power of your equipment can help you win or lose a job. When your equipment decides that, that's the day for hanging and crashing and otherwise working at a different pace from that which you would prefer. You sometimes have no option, but to call your clients, and diplomatically tell them that the work will be delayed. Do not get into the whys and the wherefores.
You tell them, so that if they were counting on or planning something based on your timelines, they can then improvise or adjust their plans accordingly. At best, they will be OK with a new timeline. At worst, they will find somebody else, to do the same within timelines they are comfortable with. Either way, speaking up works well for your reputation.
