Yes, you need it for every store. It absolutely does not imply that it would kill your memory perf by an order of magnitude! Remember that x86 does this as the

Yes, you need it for every store. It absolutely does not imply that it would kill your memory perf by an order of magnitude! Remember that x86 does this as their normal store behavior and they don't take an order of magnitude hit. The easiest approach that leads to fast release stores is just to have a stronger store pipeline that doesn't allow store-store or load-store reordring. The latter basically comes for free and most weak pipelines already preserve it. The store-store ordering, on the other hand, does have a cost: primarily in requiring stores to drain order, and handling misses in order. Nothing close to an order of magnitude. A higher performance design would allow store store reordering but not around release stores. Allowing most ARM code to the full benefit while allowing fast release stores for x86. I think you are mixing up release stores with more expensive atomics like seq-cst stores or atomic RMWs. There is no need for a store buffer drain, ever, for release stores.