急，急，急，急，急！！请教MYSQL的Replication问题

本人使用4个数据库系统，4个DB。

分别使用PIII的机器进行MYSQL的DR数据同步。
A-->A.BAK
B-->B.BAK
C-->C.BAK
D-->D.BAK

配置的4台DR的机器，近日出现越来跟不上主机的情况，看log-bin文件，最严重的相差5个log-bin文件没有同步完，看着国庆一天天过去，DR一天天跟不上，说不定哪天主机down了，备机的数据依然是相差好几个小时的数据库的数据，很是急人，不知哪位DX能帮忙看看配置，看看如何提高DR的效率？瓶颈究竟是出现在哪里？

下面是备机的my.cnf的配置，主、备都是PIII、1G内存的带raid机器，redhat系统：
[client]
port = 3306
socket = /tmp/mysql.sock

[mysqld]
port = 3306
socket = /tmp/mysql.sock
skip-locking
set-variable = key_buffer=384M
set-variable = max_allowed_packet=1M
set-variable = table_cache=512
set-variable = sort_buffer=2M
set-variable = record_buffer=2M
set-variable = thread_cache=8
set-variable = thread_concurrency=4
set-variable = myisam_sort_buffer_size=8M


log-bin = /log/log-bin
server-id = 5

innodb_data_home_dir = /db/
innodb_data_file_path = ibdata1:3200M;ibdata2:10M:autoextend
innodb_log_group_home_dir = /db/
innodb_log_arch_dir = /db/
set-variable = innodb_buffer_pool_size=384M
set-variable = innodb_additional_mem_pool_size=20M
set-variable = innodb_log_files_in_group=3
set-variable = innodb_log_file_size=100M
set-variable = innodb_log_buffer_size=8M
innodb_flush_log_at_trx_commit=1
set-variable = innodb_lock_wait_timeout=50

[mysqldump]
quick
set-variable = max_allowed_packet=16M

[mysql]
no-auto-rehash

[isamchk]
set-variable = key_buffer=256M
set-variable = sort_buffer=256M
set-variable = read_buffer=2M
set-variable = write_buffer=2M

[myisamchk]
set-variable = key_buffer=256M
set-variable = sort_buffer=256M
set-variable = read_buffer=2M
set-variable = write_buffer=2M

[mysqlhotcopy]
interactive-timeout