I just bought used IBM Thinkpad T60 with come with Intel Core 2 Duo 1.66Ghz. After I check with Intel, it’s is T5500 which is EM64T enabled, so I can use 64bit OS…
Then I upgrade the RAM to the MAX = 4GB PC 5300 DDR2.
g3ck0@linux-l90k:~> cat /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 15
model name : Intel(R) Core™2 CPU T5500 @ 1.66GHz
stepping : 6
cpu MHz : 1000.000
cache size : 2048 KB
physical id : 0
siblings : 2
core id : 0
cpu cores : 2
apicid : 0
initial apicid : 0
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 10
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe lm constant_tsc arch_perfmon pebs bts pni dtes64 monitor ds_cpl est tm2 ssse3 cx16 xtpr pdcm lahf_lm
bogomips : 3325.28
clflush size : 64
power management:
processor : 1
vendor_id : GenuineIntel
cpu family : 6
model : 15
model name : Intel(R) Core™2 CPU T5500 @ 1.66GHz
stepping : 6
cpu MHz : 1000.000
cache size : 2048 KB
physical id : 0
siblings : 2
core id : 1
cpu cores : 2
apicid : 1
initial apicid : 1
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 10
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc arch_perfmon pebs bts pni dtes64 monitor ds_cpl est tm2 ssse3 cx16 xtpr pdcm lahf_lm
bogomips : 3325.01
clflush size : 64
power management:
It’s not sufficient that the processor is 64-bit capable. The support chipset must also support more than 32-bits of addressing because some of the RAM has to be remapped above 4GB to avoid areas that are reserved for PCI address space, and other uses. So it depends on the hardware also. If you look at this specs page:
From the link given,
256MB, 512MB, 1GB, or 2GB and supports up to 4GB maximum memory
Note: Only 64-bit operating systems support more than 3GB of system memory (RAM). Intel Chipsets 945GM and 945PM do not support more than 3GB system memory (RAM), even when a 64-bit operating system is installed
Now I get it. Why I can’t get 4GB RAM due to limitation of CHIPSET. I’m using 945GM Chipset.
Firstly the kernel reserves 1GB of the address space for its own purposes so the amount of address space is reduced to 3GB. If the support chipset is capable of relocating the RAM that falls within the reserved space to a higher addresses, that’s not a problem, and you will get close to 4GB usable space (as I do with 4GB of RAM). But your chipset cannot handle > 32 address lines, so that RAM cannot be relocated. That’s the limitation of your laptop. They didn’t intend you to have more RAM than designed, to keep the cost down.
PS: It could also be that the hardware and not the the kernel cuts off access above the 3GB mark. Same effect, max RAM is 3GB then.
In this case should I use 32 bit or 64 bit, because just now, I just managed to install 64 bit on my lappy. It’s seem… there is nothing wrong, Wifi OK, Bluetooth PASS, Display n Sound Perfect…
Should I maintain it, or change back to 32 bit, is there will be a trouble for me after this…
