Ok, that's the latency of the L1 cache and that isn't shared between threads, so you might not want to count on being able to do this.
"In the case of Java volatiles, part of the solution is to force all reads/writes to bypass the local registers, and immediately trigger cache reads/writes instead. As soon as the data is read/written to the L1 cache, the hardware-coherency protocol takes over and provides guaranteed coherency across all global threads. Thus ensuring that if multiple threads are reading/writing to the same variable, they are all kept in sync with one another. And this is how you can achieve inter-thread coordination in as little as 1ns."