Jacob Gube has posted a handy chart over at Six Revisions titled "Performance Comparison of Major Web Browsers." He tests the current versions of five browsers:
In his tests he used the following performance indicators, tested three times each with an unprimed cache, and averaged the results:
Use the chart below to link to the full size version. You can also download the raw data in CSV format from the site in case you want to try your own hand at colorful charts.