1. A computer system for throttling execution in a transaction operating in a processor configured to execute memory instructions out-of-program-order in a pipelined processor, wherein memory instructions are instructions for accessing operands in memory, the computer system comprising: a memory; and a processor in communications with the memory, wherein the computer system is configured to perform a method, said method comprising: executing, by the processor, instructions of a transaction comprising: speculatively executing non-memory instructions, wherein speculative execution executes the instructions of the transaction out-of-program-order in the pipelined processor; identifying memory instructions within the transaction, wherein the memory instructions must be executed in a particular order; and based on identifying memory instructions within the transaction, marking the memory instructions as next to complete and throttling speculative execution, wherein throttling speculative execution reduces an amount of out-of-program-order executions of the instructions within the transaction.