原帖由 lnbxfzq 于 2010-1-30 22:56 发表 
晕，这个是商用2G和实际2G的区别
简单说
实际2GB=2*1024*1024*1024=2147483648B
而商用是只要达到2000000000B=1.8626GB
硬盘是这么计算的，可内存不是吧。
我贴一台服务器的，晚上回去把本机的也贴上对比一下，同样是2根2048M的内存条（linux的系统检测的结果）。
DELL 2950
==========
Handle 0x1100, DMI type 17, 28 bytes.
Memory Device
Array Handle: 0x1000
Error Information Handle: Not Provided
Total Width: 72 bits
Data Width: 64 bits
Size: 2048 MB
Form Factor: <OUT OF SPEC>
Set: 1
Locator: DIMM1
Bank Locator: Not Specified
Type: <OUT OF SPEC>
Type Detail: Synchronous
Speed: 667 MHz (1.5 ns)
Manufacturer: 830B7FB3830B
Serial Number: A329185E
Asset Tag: 0D0833
Part Number: M2D2G72TU8PD9B-3C
Handle 0x1101, DMI type 17, 28 bytes.
Memory Device
Array Handle: 0x1000
Error Information Handle: Not Provided
Total Width: 72 bits
Data Width: 64 bits
Size: 2048 MB
Form Factor: <OUT OF SPEC>
Set: 1
Locator: DIMM2
Bank Locator: Not Specified
Type: <OUT OF SPEC>
Type Detail: Synchronous
Speed: 667 MHz (1.5 ns)
Manufacturer: 830B7FB3830B
Serial Number: C0E9305D
Asset Tag: 0D0839
Part Number: M2D2G72TU8PD9B-3C
[root@zhyhl ~]# cat /proc/meminfo |grep MemTotal
MemTotal: 4043368 kB
[root@zhyhl ~]# expr 4043368 \* 1024
4140408832
[root@zhyhl ~]# expr 2048 \* 2 \* 1024 \* 1024
4294967296
Memory: 4040004k/4980736k available (2493k kernel code, 149116k reserved, 1263k data, 200k init)
[root@zhyhl ~]# expr 4040004 + 2493 + 149116 + 1263 + 200
4193076
[root@zhyhl ~]# expr 4193076 \* 1024
4293709824
[root@zhyhl ~]#
红色字体的两个数字是极度接近的。
-------------------------------------------------------------------------------------------------------------------------
Thinkpad T400
Handle 0x0007, DMI type 5, 20 bytes
Memory Controller Information
Error Detecting Method: None
Error Correcting Capabilities:
None
Supported Interleave: One-way Interleave
Current Interleave: One-way Interleave
Maximum Memory Module Size: 4096 MB
Maximum Total Memory Size: 8192 MB
Supported Speeds:
Other
Supported Memory Types:
DIMM
SDRAM
Memory Module Voltage: 2.9 V
Associated Memory Slots: 2
0x0008
0x0009
Enabled Error Correcting Capabilities:
Unknown
Handle 0x0008, DMI type 6, 12 bytes
Memory Module Information
Socket Designation: DIMM Slot 1
Bank Connections: 0 1
Current Speed: 42 ns
Type: DIMM SDRAM
Installed Size: 2048 MB (Double-bank Connection)
Enabled Size: 2048 MB (Double-bank Connection)
Error Status: OK
Handle 0x0009, DMI type 6, 12 bytes
Memory Module Information
Socket Designation: DIMM Slot 2
Bank Connections: 2 3
Current Speed: 42 ns
Type: DIMM SDRAM
Installed Size: 2048 MB (Double-bank Connection)
Enabled Size: 2048 MB (Double-bank Connection)
Error Status: OK
[root@think ~]# cat /proc/meminfo |grep MemTotal
MemTotal: 3973316 kB
[root@think ~]# expr 3973316 \* 1024
4068675584
[root@think ~]# expr 2048 \* 2 \* 1024 \* 1024
4294967296
[root@think ~]#
Memory: 3969836k/5177344k available (2547k kernel code, 152752k reserved, 1289k data, 208k init)
[root@think ~]# expr 3969836 + 2547 + 152752 + 1289 + 208
4126632
[root@think ~]# expr 4126632 \* 1024
4225671168
[root@think ~]#
###########################################################
两台机器的对比相差较大:
[root@zhyhl ~]# expr 2048 \* 2 \* 1024 \* 1024
4294967296
[root@zhyhl ~]# expr 4193076 \* 1024
4293709824 <---- dell 2950
[root@think ~]# expr 4126632 \* 1024
4225671168 <---- thinkpad
顺便提一下, 这个Thinkpad可以支持到8G，如下所示
Maximum Memory Module Size: 4096 MB
Maximum Total Memory Size: 8192 MB
[ 本帖最后由 becvx 于 2010-2-1 19:34 编辑 ] |
发表于 2010-1-30 20:18
| 
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