1. A method comprising: executing a transactional memory (TM) transaction in a first thread; determining if a write of data to be performed in the TM transaction is sized to fit within a hardware buffer; if so, determining whether a copy of the data is present in the hardware buffer and if so updating the data in the hardware buffer using a user-level buffered store instruction to write the data, wherein the user-level buffered store instruction is to further indicate that the data is locally visible to the first thread but not globally visible; and if the copy is not present in the hardware buffer, creating a buffered copy of the data at a location of the hardware buffer using the user-level buffered store instruction, and updating the data in the buffered copy using the user-level buffered store instruction.