In IBM systems terminology, RAMP-C was an earlier performance test that was replaced in the mid-1990s by the Commercial Processing Workload (CPW) benchmark for measuring the relative performance of systems like the AS/400 and its successors (IBM iSeries, IBM i, and Power Systems).
RAMP-C
RAMP-C (an acronym likely for something like “Relative AS/400 Multiprocessor Performance – Commercial” or similar, though the exact full name is not specified in the sources) was a transaction processing test used to gauge the performance of early IBM midrange systems. It was the original touchstone for relative performance, with the baseline AS/400 9404-B10 machine given a rating of 1.0 on this test.
CPW
The CPW rating replaced the RAMP-C in 1996 and has been the standard for measuring commercial performance ever since.
Basis : The CPW test is loosely based on the Transaction Processing Council’s TPC-C benchmark test but is an IBM-internal, I/O intensive workload designed to evaluate the system and associated software in a commercial environment.
Usage : The CPW benchmark provides a standard, consistent measure that allows customers to compare the relative processing power of different
IBM i on Power systems.
Measurement : The CPW is measured using a specific workload maintained internally by the IBM i Systems Performance group. Performance information and CPW ratings for various models are published in documents such as the “IBM i on Power Performance FAQ” and “Performance Capabilities Reference” guides, available on the IBM website.
Conversion and Comparison
While a simple formula does not exist, historical IBM performance documents sometimes provided “bridge” comparisons for specific, older machine models to help users transition to the new metric. These comparisons were specific to a particular hardware generation and OS version.
These varying values illustrate that the conversion is not a simple multiplication factor but is dependent on the specific system configuration, operating system version, and the nature of the actual workload.
To find comparable performance information for specific legacy systems, you would need to consult original, archived IBM performance documentation such as the “AS/400 Performance Capabilities Reference” from the mid-to-late 1990s, available in PDF format on various online archives.