Modifying prefetch request processing. A prefetch request is received by a local computer from a remote computer. The local computer responds to a determination that execution of the prefetch request is predicted to cause an address conflict during an execution of a transaction of the local processor by comparing a priority of the prefetch request with a priority of the transaction. Based on a result of the comparison, the local computer modifies program instructions that govern execution of the program instructions included in the prefetch request to include program instruction to perform one or both of: (i) a quiesce of the prefetch request prior to execution of the prefetch request, and (ii) a delay in execution of the prefetch request for a predetermined delay period.