Mozilla execs may have said they weren’t worried about Chrome, but now the company is fighting back against Google’s browser offering with a new speed test showing its performance compared to the upcoming Firefox 3.1. Specifically, the tests compare Chrome’s V8 open source Javascript engine with the new Firefox’s TraceMonkey engine.

Mozilla claims its offering ran 28 percent faster than Chrome on XP systems and 16 percent faster on Vista. Brenden Eich of TraceMonkey jokingly suggested he should rename the TraceMonkey technology to “V10,” a clear indication of his team’s awareness of Chrome’s quickly gained reputation for speed dominance.

The new Firefox 3.1 is set to be released before the year’s end.

Meanwhile, in case you were wondering how much people really care about Chrome, some new numbers out this afternoon give us a glimpse, at least in one country. HitWise looked at UK traffic on the browser’s launch day Tuesday and found visits to the Chrome site accounted for 0.6 percent of the nation’s overall traffic — a figure lower than the number of visits to either Microsoft’s or Mozilla’s respective software pages. Most people stayed on the Chrome site for about two minutes.