[HELP]: comparing 2 specific CPUs

Hi,

I need to build 2 Asterisk servers in a HA cluster with about 80-100 concurrent calls (most will be SIP/SIP-iLBC and the rest will be SIP/ZAP-PRI-BRI), very little MOH and limited voicemail. Each server will have 1-port PRI card, 1 4-port BRI card with hardware echo cancellation and 1 4-port FXO analog card (Asterisk will be doing software echo cancellation on these 4 channels but that will be obviously limited to just 4 echo cancelled channels at a time).

After searching for many products and considering their prices it boiled down to comparing these two microprocessors (which rate practically the same):

AMD AM2 ATHLON 64 6400+ D-CORE (3200 MHz)

INTEL QUAD 6600 2.4 GHZ SK775 1066 MHZ 8MB QUAD CORE

Which one would you buy if you were in my place?
Please don’t make it an AMD/Intel debate. All I really need to understand is if QUAD can actually benefit Asterisk (the way it’s programmed)) or if it’s better to go with less cores but higher frequency (3GHz).

Thank you for your time,

Vieri