FYI, this is a profile of my Tor v0.2.2.30-rc relay, taken in a 10-minute sampling:
CPU: CPU with timer interrupt, speed 0 MHz (estimated) Profiling through timer interrupt samples % linenr info symbol name 3126 29.7290 cast-586.s:9 CAST_encrypt 1677 15.9486 sha256-586.s:8 sha256_block_data_order 1149 10.9272 aes-586.s:424 _x86_AES_encrypt 844 8.0266 sha1-586.s:8 sha1_block_data_order 273 2.5963 crypto.c:1649 crypto_digest_get_digest 221 2.1018 md32_common.h:283 SHA1_Update 182 1.7309 encode.c:190 EVP_EncodeBlock 171 1.6262 OpenBSD_malloc_Linux.c:1793 ifree 136 1.2934 cast-586.s:379 CAST_decrypt 130 1.2363 md32_common.h:348 SHA1_Final 127 1.2078 obj_lib.c:66 OBJ_dup 122 1.1602 memarea.c:221 memarea_alloc 110 1.0461 aes-586.s:1610 _x86_AES_decrypt
After running for 14 hours, the Tor relay has consumed 1.6% of CPU time. It is now using 45MB of RAM, servicing 112 active connections.
According to http://torstatus.blutmagie.de my Max/Burst/Observed (Bps) bandwidth is:
153600 / 307200 / 127170
Environment:
CPU: Pentium-M (Dothan) @ 1.80 GHz RAM: 1.0 GB DDR1 Net: Fast Ethernet connected to a Surfboard cable modem
CentOS v5.6 Tor v0.2.2.30-rc libevent 2.0.12-stable openssl 1.0.0d zlib 1.2.5 glibc 2.5-58
Just another data point.