64bit CPUs

Mariusz Grad mariusz.grad at pwr.wroc.pl
Mon May 2 05:16:35 PDT 2005

Mike Tancsa:
> A somewhat obvious question to some perhaps, but what server application 
> mix on FreeBSD today sees an improvement using 64bit CPUs ?  In my ISP 
> centric world, my big apps are BIND, IMAP/POP3, httpd via apache, SMTP, AV 
> and SPAM scanning, and firewalls/routing.  Apart from larger RAM, why would 
> these benefit from the 64bit world ?  Or would they ?
Benefits from AMD64:
- larger RAM limit (40bit memory address),
- 64bit GRPs,
- much faster access to memory (memory controller inside core - no northbridge),
- it much better scales (with many CPUs) (he doesnt share memory bandwith),
- large caches L1 = 64KB, L2 = 1MB (comparing to xeon 12/512K),
- DEP = Data Execution Protection (it has to be supported via OS),
- Multimedia Extensions for graphics / vector processing.
= Opterons remove memory bottlenecks espacially with multi-cpus.

Ive had large acceleration at:
- math computation (f77, 2-4GB double precision matrix) single opteron 1.8GHz (sun v20z) was 4x faster then celeron 2.4GHz.
- databases (pgsql) Opteron 1.8 GHz 2x faster then Xeon 3.2

I would assume that everything which can run:
- in parallel,
- on multi-Opterons CPU,
- which uses heavly RAM,
- which can take benefits from 64bit registers (floating points),
will have _extreamly_ boost comparing to Intels EMT64 (or Itanium2).

Mariusz Grad / UNIX Systems Administrator
tel: +4871 320-2520 mobile: +48 501-134-008
Wroclaw Centre for Networking and Supercomputing 
address: Wybrzeze Wyspianskiego 27, Wroclaw, Poland

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