This is somewhat optimized my.cnf for someone. How is it? This box has 1GB RAM and a 1.8 GHz celeron cpu. Need an insight into improving performance. show full processlist suggests select, order by type queries.

# cat /etc/my.cnf 
[mysqld]
set-variable = max_connections=500
safe-show-database
skip-name-resolve
query_cache_size = 52428800
query_cache_type = 1
log-slow-queries=var/log/mysqld.slow.log
key_buffer_size=104857600
read_buffer_size=512000
table_cache=512