Xeon w/ L3 1MB cache vs Xeon w/o L3 cache

[Simon]

Has anyone done any comparison to see if extra L3 cache on Xeon CPUs
provides any benefit to FreeBSD's kernel/core services and various user
services' (http/email/ftp/databases) performance? I read that L3 can make
things slower instead of faster in cases where L3 is not utilized and the CPU
is forced to access it anyway (when L1/L2 don't hold the data it wants),
because it exists. Would anyone with personal experience with Xeon CPUs
with and without L3 cache comment on the impact of L3 cache. Any links
to any related articles would be appreciated, as well.

Thank you!

-Simon