  The computing performance today is developing mainly using parallelized
sequential computing, in many forms. The paper scrutinizes whether the
performance of that type of computing has an upper limit. The simple
considerations point out that the theoretically possible upper bound is
practically achieved, and that the main obstacle to step further is the
presently used computing paradigm and implementation technology. In addition to
the former "walls", also the "performance wall" must be considered. As the
paper points out, similarly to the "dark silicon", also the "dark performance"
is always present in the parallelized many-processor systems.
