1. A method of generating a distribution of performance ratios between multiple computer systems, the method comprising: in a system that includes at least one microprocessor, application-specific integrated circuit, or programmable logic device: for each computer system, obtaining results from multiple tests configured to test performance of the computer systems; for each of the multiple tests, calculating a ratio between the computer systems' test results, wherein calculating the ratio involves dividing a result or a combination of results from a first computer system from the multiple computer systems for a given test by a result or a combination of results from a second computer system from the multiple computer systems for the given test; weighting one or more of the calculated ratios relative to an expected use of the computer systems by a user; generating a histogram from the calculated ratios to indicate a distribution of the calculated ratios; and from the histogram, predicting a probability of an expected level of performance of one of the computer systems compared to another of the computer systems.