Apps optimized for 64 bits?

[tji]

Hi, I'm a newbie to gentoo.. I'm currently running an Athlon 64 system (Asus K8V Deluxe motherboard) in 32 bit mode and I'm wondering if it's time to make the jump yet.

These questions are not really gentoo specific. But, I have not found any better place discussing x86-64 specific issues. Also, this info could be good for people wondering why x86-64 linux is important..


I've seen a lot of discussion about apps that can be compiled in 64 bit more. But, are there many apps that have been specifically optimized to take advantage of a 64 bit environment or other Athlon64 improvements? I would think that some of the big number crunching apps, like crypto or MPEG2/4 video would benefit..

How about general Linux info on x86-64, such as:

- I read that x86-64 supports per-page permissions, so it can prevent many buffer overflow exploits. Is this enabled in the current linux kernels?
- Is the "Cool n Quiet" feature enabled in linux? (To throttle cpu speed based on performance needs)

[malte]

[Sivar]

The most globally significant AMD64 long-mode improvement, namely having twice as many general purpose registers, does not require optimization for use at the source-code level.
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[torne]

AMD64 chips run all ordinary untweaked code faster than an Athlon XP even in 32-bit mode (just from being a better microarchitecture and having more cache); ordinary code compiled 64-bit is normally a little bit faster still (by using more general purpose registers). The optimisation you want in encoders to get maximal performance is to use SSE2 operations (which are not available on AthlonXP), but this requires the code to be written specifically for amd64 (32-bit SSE2 code will not be as fast or perhaps not work at all).