SSE4 is a SIMD CPU instruction set used in the Intel Core microarchitecture and AMD K10 (K8L). It was announced on September 27, 2006, at the Fall 2006 Intel Developer Forum, with vague details in a white paper; more precise details of 47 instructions became available at the Spring 2007 Intel Developer Forum in Beijing, in the presentation. SSE4 extended the SSE3 instruction set which was released in early 2004. All software using previous Intel SIMD instructions are compatible with modern microprocessors supporting SSE4 instructions. All existing software continues to run correctly without modification on microprocessors that incorporate SSE4, as well as in the presence of existing and new applications that incorporate SSE4.