Optimization on MariaDB, need some advice...

[rdn]

Server Specs:
CPU: Intel i5 (4 cores / 4 Threads)
Frequency: 3.1GHz (3.8GHz Turbo Boost)
RAM: 8 GB DDR3
CentOS 6.5 Server
Nginx 1.5.7
Php 5.5.7
Using APC
MariaDb latest version

Here's my /etc/my.cnf:

[mysqld]
#character-set-server=utf8
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock

#tmpdir=/home/mysqltmp

#skip-innodb
skip-federated
#skip-pbxt
#skip-pbxt_statistics
skip-archive
#skip-name-resolve
#old_passwords
back_log = 75
max_connections = 300
key_buffer_size = 1024M
myisam_sort_buffer_size = 32M
myisam_max_sort_file_size = 2048M
join_buffer_size = 256K
read_buffer_size = 256K
sort_buffer_size = 512K
table_definition_cache = 4096
table_open_cache = 4096
thread_cache_size = 64
wait_timeout = 120
connect_timeout = 10
tmp_table_size = 256M
max_heap_table_size = 256M
max_allowed_packet = 32M
max_seeks_for_key = 1000
group_concat_max_len = 1024
max_length_for_sort_data = 1024
net_buffer_length = 16384
max_connect_errors = 100000
concurrent_insert = 2
read_rnd_buffer_size = 256K
bulk_insert_buffer_size = 8M
query_cache_limit = 512K
query_cache_size = 32M
query_cache_type = 1
query_cache_min_res_unit = 2K
query_prealloc_size = 262144
query_alloc_block_size = 65536
transaction_alloc_block_size = 8192
transaction_prealloc_size = 4096
default-storage-engine = InnoDB

log_warnings=1
slow_query_log=0
long_query_time=1
slow_query_log_file=/var/lib/mysql/slowq.log
log-error=/var/log/mysqld.log

# innodb settings
#innodb_extra_rsegments = 4
innodb_purge_threads=1
innodb_doublewrite = 1

innodb_file_per_table = 1
innodb_open_files = 1000
innodb_data_file_path= ibdata1:10M:autoextend
innodb_buffer_pool_size = 2G
innodb_additional_mem_pool_size = 32M

innodb_log_files_in_group = 2
innodb_log_file_size = 64M
innodb_log_buffer_size = 8M
innodb_flush_log_at_trx_commit = 2
innodb_thread_concurrency = 0
innodb_lock_wait_timeout=50
innodb_flush_method = O_DIRECT
innodb_support_xa=1

# 200 * # DISKS
innodb_io_capacity = 100
innodb_read_io_threads = 2
innodb_write_io_threads = 2

# mariadb settings
[mariadb]
#thread-handling = pool-of-threads
#thread-pool-size= 20
#mysql --port=3307 --protocol=tcp
#extra-port=3307
#extra-max-connections=1

userstat = 0
key_cache_segments = 1
aria_group_commit = none
aria_group_commit_interval = 0
aria_log_file_size = 32M
aria_log_purge_type = immediate
aria_pagecache_buffer_size = 8M
aria_sort_buffer_size = 8M

[mariadb-5.5]
#ignore_db_dirs=
query_cache_strip_comments=0

#innodb_lazy_drop_table=1
innodb_read_ahead = linear
innodb_adaptive_flushing_method = estimate
innodb_flush_neighbor_pages = 1
innodb_stats_update_need_lock = 0
innodb_log_block_size = 512

log_slow_filter =admin,filesort,filesort_on_disk,full_join,full_scan,query_cache,query_cache_miss,tmp_table,tmp_table_on_disk

[mysqld_safe]
socket=/var/lib/mysql/mysql.sock
log-error=/var/log/mysqld.log
#nice = -5
open-files-limit = 8192

[mysqldump]
quick
max_allowed_packet = 32M

[myisamchk]
key_buffer = 32M
sort_buffer = 16M
read_buffer = 16M
write_buffer = 16M

[mysqlhotcopy]
interactive-timeout