  Quantum volume (QV) has become the de-facto standard benchmark to quantify
the capability of Noisy Intermediate-Scale Quantum (NISQ) devices. While QV
values are often reported by NISQ providers for their systems, we perform our
own series of QV calculations on 24 NISQ devices currently offered by IBM Q,
IonQ, Rigetti, Oxford Quantum Circuits, and Quantinuum (formerly Honeywell).
Our approach characterizes the performances that an advanced user of these NISQ
devices can expect to achieve with a reasonable amount of optimization, but
without white-box access to the device. In particular, we compile QV circuits
to standard gate sets of the vendor using compiler optimization routines where
available, and we perform experiments across different qubit subsets. We find
that running QV tests requires very significant compilation cycles, QV values
achieved in our tests typically lag behind officially reported results and also
depend significantly on the classical compilation effort invested.
