On 3 September 2010 07:51, Mike Beltzner <beltz...@mozilla.com> wrote:
> [..] > * We are considering dropping support for i386 architectures which do not > support SSE2  (older Athlon CPUs, some VIA chipsets) but have not yet > reached a final decision here.
There was a thread on this back in December. I think the outcome was that it was a clear "collect more data".
On an anecdotal note, I know of several machines still in active use (some even that have just even have just been updated do windows 7) that would be disadvantaged by this change. Diverging from OS requirements (as I stated before, Windows 7 supports non-sse2 systems) could be confusing.
> Don't expect your websites to render any faster, just because Firefox can address more memory!
Performance of 32-bit vs 64-bit code really depends on the workload; for a lot of things we do the extra registers make a noticeable difference and we get a speedup (even in spite of the higher cache pressure 64-bit builds entail).
Last I measured, for DOM operations we're talking about 20%, at least on Mac.