求助mysql innodb_buffer_pool_size 设置超过1G服务启动就报错

innodb_buffer_pool_size 设成2G就服务就起不来，1G就OK   
win2008 64位操作系统   mysql5.5
16核，24G内存   求助151119 20:12:53 [Note] Plugin 'FEDERATED' is disabled.
151119 20:12:53 InnoDB: The InnoDB memory heap is disabled
151119 20:12:53 InnoDB: Mutexes and rw_locks use Windows interlocked functions
151119 20:12:53 InnoDB: Compressed tables use zlib 1.2.3
151119 20:12:53 InnoDB: Initializing buffer pool, size = 2.0G
InnoDB: VirtualAlloc(2175795200 bytes) failed; Windows error 8
151119 20:12:53 InnoDB: Completed initialization of buffer pool
151119 20:12:53 InnoDB: Fatal error: cannot allocate memory for the buffer pool
151119 20:12:53 [ERROR] Plugin 'InnoDB' init function returned error.
151119 20:12:53 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
151119 20:12:53 [ERROR] Unknown/unsupported storage engine: INNODB
151119 20:12:53 [ERROR] Aborting
my.ini
[client]
port=3306
[mysql]
default-character-set=utf8
[mysqld]
port=3306
tmpdir ="D:/mysql/temp"
basedir="D:/mysql/"
datadir="D:/mysql/Data/"
character-set-server=utf8
default-storage-engine=INNODB
sql-mode="STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION"
max_connections=1000
query_cache_size=0
table_cache=512
tmp_table_size=512M
thread_cache_size=128
myisam_max_sort_file_size=100G
myisam_sort_buffer_size=512M
key_buffer_size=1024M
read_buffer_size=8M
read_rnd_buffer_size=1M
sort_buffer_size=8M
innodb_additional_mem_pool_size=16M
innodb_flush_log_at_trx_commit=2
innodb_file_per_table=1
innodb_log_buffer_size=7M
innodb_buffer_pool_size=1G
innodb_log_file_size=343M
innodb_thread_concurrency=34
max_allowed_packet=500M