On my machine given my unscientific measurements in Q2 2009:
V8 and JavaScriptCore are really, really fast.
TraceMonkey is fast, but often far behind really, really fast.
V8: Chromium 3.0.182 (182.0) snapshot 16837 23 May 2009
TraceMonkey: Firefox 3.6a1pre nightly latest-trunk 22 May 2009
JavaScriptCore (SquirrelFish extreme): WebKit r44078 nightly 23 May 2009
- Dromaeo JavaScript Tests (higher is better):
- V8: 175 runs/s
- JavaScriptCore: 195 runs/s
- TraceMonkey: 53 runs/s
- V8: 175 runs/s
- V8 Benchmark Suite version 4 (higher is better):
- V8: 2324
- JavaScriptCore: 1882
- TraceMonkey: 289
- V8 Benchmark Suite version 3 (higher is better):
- V8: 2109
- JavaScriptCore: 2079
- TraceMonkey: 281
- SunSpider 0.9 (lower is better):
- V8: 859ms
- JavaScriptCore: 860ms
- TraceMonkey:1430ms

For the SunSpider bars lower is better, for the others higher is better. Read the previous post for more information.