Microsoft’s Scott Guthrie spoke of “twice as fast performance” in the newly-released Silverlight 4, thanks to a new just-in-time compiler.
Performance is a hard thing to nail down. Maybe he meant that compilation is twice as fast? I’m not sure; but I tried a couple of quick tests.
First, I looked at my Primes test. Version 3 running in Windows Vista took around 0.40 seconds (the exact figure varies on each run, thanks to background processes or other factors). I then upgraded to version 4.0. No significant difference, on average over several runs. I used Vista because I’d already upgraded my Windows 7 install.
Next I tried Bubblemark. I maxed it out at 128 bubbles. On Vista with Silverlight 3 I got about 240 fps; on the same machine with Silverlight 4 about 260fps; about 8%.
Next I tried on an Apple Mac. My Mac Mini is less powerful, though not that bad, an Intel 1.83 Ghz Core Duo. On the Prime test I got 0.54 secs before, and 0.50 secs after the upgrade to 4.0, about 7.5% improvement. On Bubblemark, it was only 24 fps before and after.
I guess the vast difference in graphics performance is also interesting. It is not just Mac vs Windows; the Nvidia GeForce 6800 on the PC is more powerful than whatever is in the Mac Mini.
If anyone can tell me in what respect version 4.0 is twice as fast, I’d be grateful.
Update: prompted by the comment from David Heffernan below, I also tried the Encog Silverlight Benchmark. I used an older core duo laptop, since I am running out of machines to upgrade. I ran the test twice before upgrading, and twice after. Lower is better:
Silverlight 3.0: 22.0
Silverlight 4.0: 12.7
That’s about 42% better, where “twice as fast” would be 50% better, much closer to Guthrie’s claim. I guess it depends what you measure.