The dmidecode utility will display the SMBIOS (System Management BIOS) or the DMI (Desktop Management Interface) table. It can be very useful to determine your current hardware and other good information.

To display type options:

# dmidecode -t
Type number or keyword expected
Valid type keywords are:
bios
system
baseboard
chassis
processor
memory
cache
connector
slot

Here is an example:
# dmidecode -t processor
# dmidecode 2.9
SMBIOS 2.3 present.

Handle 0x0400, DMI type 4, 35 bytes
Processor Information
Socket Designation: Proc_1
Type: Central Processor
Family: Pentium 4
Manufacturer: Intel
ID: 29 0F 00 00 FF FB EB BF
Signature: Type 0, Family 15, Model 2, Stepping 9
Flags:
FPU (Floating-point unit on-chip)
VME (Virtual mode extension)
DE (Debugging extension)
PSE (Page size extension)
TSC (Time stamp counter)
MSR (Model specific registers)
PAE (Physical address extension)
MCE (Machine check exception)
CX8 (CMPXCHG8 instruction supported)
APIC (On-chip APIC hardware supported)
SEP (Fast system call)
MTRR (Memory type range registers)
PGE (Page global enable)
MCA (Machine check architecture)
CMOV (Conditional move instruction supported)
PAT (Page attribute table)
PSE-36 (36-bit page size extension)
CLFSH (CLFLUSH instruction supported)
DS (Debug store)
ACPI (ACPI supported)
MMX (MMX technology supported)
FXSR (Fast floating-point save and restore)
SSE (Streaming SIMD extensions)
SSE2 (Streaming SIMD extensions 2)
SS (Self-snoop)
HTT (Hyper-threading technology)
TM (Thermal monitor supported)
PBE (Pending break enabled)
Version: Not Specified
Voltage: 1.5 V
External Clock: 533 MHz
Max Speed: 3200 MHz
Current Speed: 2800 MHz
Status: Populated, Enabled
Upgrade: ZIF Socket
L1 Cache Handle: 0x0700
L2 Cache Handle: 0x0701
L3 Cache Handle: Not Provided
Serial Number: Not Specified
Asset Tag: Not Specified
Part Number: Not Specified

Handle 0x0401, DMI type 4, 35 bytes
Processor Information
Socket Designation: Proc_2
Type: Central Processor
Family: Pentium 4
Manufacturer: Intel
ID: 00 00 00 00 00 00 00 00
Signature: Type 0, Family 0, Model 0, Stepping 0
Flags: None
Version: Not Specified
Voltage: 1.5 V
External Clock: 533 MHz
Max Speed: 3200 MHz
Current Speed: Unknown
Status: Unpopulated
Upgrade: ZIF Socket
L1 Cache Handle: 0x0703
L2 Cache Handle: 0x0704
L3 Cache Handle: Not Provided
Serial Number: Not Specified
Asset Tag: Not Specified
Part Number: Not Specified