MySQL 5.0.67 is faster than 5.5.15

Hi,
I compare performance of 5.0 and 5.5 at FreeBSD 7.4.
I have two identical servers:
2x X5687 3.6GHz
98GB
8x HDD 146GB

RAID at srv01:

Id Size Level Stripe State Cache Name mfid0 ( 544G) RAID-1 64K OPTIMAL Writes

RAID at srv02:

Id Size Level Stripe State Cache Name mfid0 ( 952G) RAID-5 128K OPTIMAL Writes

I run sysbench as follows:
MyISAM warmup:

–test=oltp --mysql-db=test --oltp-table-name=sbtest_myisam --max-time=120 --max-requests=0 --num-threads=8 --mysql-socket=/tmp/mysql.sock --oltp-read-only=on run

MyISAM r/o test:

–test=oltp --mysql-db=test --oltp-table-name=sbtest_myisam --max-time=60 --max-requests=0 --num-threads=$i --mysql-socket=/tmp/mysql.sock --oltp-read-only=on run

InnoDB warmup:

–test=oltp --mysql-db=test --oltp-table-name=sbtest_innodb --max-time=120 --max-requests=0 --num-threads=8 --mysql-socket=/tmp/mysql.sock --oltp-read-only=on run

InnoDB r/o test:

–test=oltp --mysql-db=test --oltp-table-name=sbtest_innodb --max-time=60 --max-requests=0 --num-threads=$i --mysql-socket=/tmp/mysql.sock --oltp-read-only=on run

InnoDB r/w test:

–test=oltp --mysql-db=test --oltp-table-name=sbtest_innodb --max-time=60 --max-requests=0 --num-threads=$i --mysql-socket=/tmp/mysql.sock run

What I get is 5.5 defeat:

num-threads 1 2 3 4 5 6 7 8 10 12 14 16 18 20 22 24 26 28 30 32 36 40 44 48 52 56 60 64srv01: MySQL 5.0.67MyISAM-RO, tps 426.71 725.57 973.66 1156.96 1272.73 1226.91 1139.41 1037.77 887.3 753.07 627.38 523.83 462.76 400.93 348.95 302.41 289.03 259.91 251.23 234.1 216.87 198.67 194.87 185.09 182.66 176.76 173.1 170.83InnoDB-RO, tps 340.64 677.72 1003.94 1322.52 1579.73 1805.14 2011.87 2216.72 2452.15 2644.93 2807.23 2902.67 2812.12 2738.45 2691.59 2668.98 2654.41 2649.93 2641.42 2619.1 2601.82 2567.7 2456.73 2429.16 2328.02 2285.03 2210.29 2181.58InnoDB-RW, tps 282.55 538.73 757.27 977.01 1169.77 1330.55 1466.86 1575.6 1735.46 1786.18 1761.36 1757.96 1741.73 1722.25 1658.2 1610.09 1583.49 1582.79 1566.43 1547.11 1478.27 1246 1177.73 786.99 753.66 516.18 627.72 683.74srv02: MySQL 5.5.15MyISAM-RO, tps 415.05 716.39 953.74 1164.5 1252.94 1178.99 1054.93 938.62 895.02 813.39 698.7 592.76 537.41 509.51 491.63 473.91 461.51 448.63 438.83 429.39 414.73 398.43 391.88 418.6 473.02 532.58 585.42 633.26InnoDB-RO, tps 329.41 644.44 942.18 1270.56 1536.27 1817.91 2091.28 2360.85 2253.96 2235.38 2227.67 2230.93 2249.48 2257.12 2262.33 2267.69 2277.28 2281.22 2283.75 2282.72 2289.74 2291.23 2289.82 2290.47 2289.81 2286.34 2284.71 2281.92InnoDB-RW, tps 263.08 500.49 725.2 958.81 1141.32 1295.54 1440.64 1557.53 1607.25 1611.72 1619.78 1617.16 1568.26 1417.52 1419.97 1415.19 1400.13 1401.08 1315 1309.76 1302.36 1280.06 1271.39 1259.55 1245.41 1240.26 1218.8 1199.69

What is a possible reason: misconfiguration, OS, RAID, something else?

The following my.cnf is used:

back_log = 100binlog_cache_size = 1Mconnect_timeout = 5delayed_insert_limit = 10000delayed_insert_timeout = 100delayed_queue_size = 8000000expire_logs_days = 5ft_min_word_len = 4innodb_additional_mem_pool_size = 20Minnodb_buffer_pool_size = 40Ginnodb_data_file_path = ibdata1:10M:autoextendinnodb_flush_log_at_trx_commit = 1innodb_flush_method = O_DIRECTinnodb_lock_wait_timeout = 300innodb_locks_unsafe_for_binlog = 1innodb_log_buffer_size = 16Minnodb_log_file_size = 1900Minnodb_status_file = 0innodb_thread_concurrency = 0interactive_timeout = 120join_buffer_size = 1Mkey_buffer_size = 6Gmax_allowed_packet = 1Mmax_connect_errors = 10max_connections = 200max_heap_table_size = 64Mmax_user_connections = 200myisam_sort_buffer_size = 4Gskip-external-lockingskip-name-resolvesort_buffer_size = 64Ksync_binlog = 1table_cache = 2048thread_cache_size = 286thread_stack = 196Ktmp_table_size = 64Mtransaction_isolation = REPEATABLE-READwait_timeout = 120

Could you check the performance of your disks? In particular, I’m curious about how you got 544G with RAID1. RAID10 is faster than RAID5, in general.

Please, what role can play disks in memory-bound test?
Nevertheless,

$ iostat -dx 5 extended device statisticsdevice r/s w/s kr/s kw/s wait svc_t %bmfid0 0.8 63.5 8.6 2799.4 0 0.8 1 extended device statisticsdevice r/s w/s kr/s kw/s wait svc_t %bmfid0 0.0 0.0 0.0 0.0 0 0.0 0 extended device statisticsdevice r/s w/s kr/s kw/s wait svc_t %bmfid0 0.0 0.0 0.0 0.0 0 0.0 0 extended device statisticsdevice r/s w/s kr/s kw/s wait svc_t %bmfid0 0.0 2.8 0.0 44.8 0 0.2 0 extended device statisticsdevice r/s w/s kr/s kw/s wait svc_t %bmfid0 0.0 3.4 0.0 9.2 0 0.1 0