cpu throttling log

[farsgsm]

Dear friends,

my host fell in cpu throttling many times daily...
i cheked mysqlslow queris log and i see this info

# Sat Sep 12 05:33:52 2009
# Query_time: 10 Lock_time: 0 Rows_sent: 0 Rows_examined: 0
use ****mc_vb2;
SELECT postid, wordid,
CASE intitle
WHEN 0 THEN score
WHEN 1 THEN score + 5
WHEN 2 THEN score + 5 + 5
ELSE score
END AS score
FROM postindex
WHERE wordid IN (0,546,1842,7101,168,207,26040,535,209,580)

# Sat Sep 12 05:51:39 2009
# Query_time: 2 Lock_time: 0 Rows_sent: 0 Rows_examined: 0
use ****mc_vb2;
SELECT postid
FROM post AS post
INNER JOIN thread AS thread ON(thread.threadid = post.threadid)
WHERE post.userid = 4163
AND post.post_thanks_amount != 0
AND thread.forumid IN(1,45,123,47,46,2,3,5,8,14,6,11,4,13,9,10,12,7,1 5,16,94,87,90,132,18,149,22,17 ,19,110,126,20,111,127,21,112,128,75,113,129,108,1 14,130,23,30,95,190,26,164,78, 125,88,80,97,28,29,27,82,124,109,76,25,92,79,83,10 7,91,89,99,24,85,74,81,96,157, 158,166,167,168,181,182,183,184,159,60,63,64,176,1 77,160,172,173,174,175,178,179 ,69,70,72,180,185,186,187,188,115,131,116,101,100, 102,150,151,156,103,152,155,10 6,105,153,154,104,35,77,191,36,37,38,39,40,41,86,4 2,133,52,84,134,135,141,136,13 9,140,143,142,138,144,137,145,148,165,48,44,49,73, 147,146,50,51)
ORDER BY post.dateline DESC
LIMIT 1000

what does it mean
what plugins or something esle i have to disable to make cpu ok