Intel-defined CPU features, CPUID level 0x00000001 (edx) See also Wikipedia and table 2-27 in Intel Advanced Vector Extensions Programming Reference fpu: Onboard FPU (floating point support) vme: Virtual Mode Extensions (8086 mode) de: Debugging Extensions (CR4.DE) pse: Page Size Extensions (4MB memory pages) tsc: Time Stamp Counter (RDTSC) msr: Model-Specific Registers (RDMSR, WRMSR) pae: Physical Address Extensions (support for more than 4GB of RAM) mce: Machine Check Exception cx8: CMPXCHG8 instruction (64-bit compare-and-swap) apic: Onboard APIC sep: SYSENTER/SYSEXIT mtrr: Memory Type Range Registers pge: Page Global Enable (global bit in PDEs and PTEs) mca: Machine Check Architecture cmov: CMOV instructions (conditional move) (also FCMOV) pat: Page Attribute Table pse36: 36-bit PSEs (huge pages) pn: Processor serial number clflush: Cache Line Flush instruction dts: Debug Store (buffer for debugging and profiling instructions) acpi: ACPI via MSR (temperature monitoring and clock speed modulation) mmx: Multimedia Extensions fxsr: FXSAVE/FXRSTOR, CR4.OSFXSR sse: Intel SSE vector instructions sse2: SSE2 ss: CPU self snoop ht: Hyper-Threading tm: Automatic clock control (Thermal Monitor) ia64: Intel Itanium Architecture 64-bit (not to be confused with Intel's 64-bit x86 architecture with flag x86-64 or "AMD64" bit indicated by flag lm) pbe: Pending Break Enable (PBE# pin) wakeup support AMD-defined CPU features, CPUID level 0x80000001 See also Wikipedia and table 2-23 in Intel Advanced Vector Extensions Programming Reference syscall: SYSCALL (Fast System Call) and SYSRET (Return From Fast System Call) mp: Multiprocessing Capable. nx: Execute Disable mmxext: AMD MMX extensions fxsr_opt: FXSAVE/FXRSTOR optimizations pdpe1gb: One GB pages (allows hugepagesz=1G) rdtscp: Read Time-Stamp Counter and Processor ID lm: Long Mode (x86-64: amd64, also known as Intel 64, i.e. 64-bit capable) 3dnowext: AMD 3DNow! extensions 3dnow: 3DNow! (AMD vector instructions, competing with Intel's SSE1) Transmeta-defined CPU features, CPUID level 0x80860001 recovery: CPU in recovery mode longrun: Longrun power control lrti: LongRun table interface Other features, Linux-defined mapping cxmmx: Cyrix MMX extensions k6_mtrr: AMD K6 nonstandard MTRRs cyrix_arr: Cyrix ARRs (= MTRRs) centaur_mcr: Centaur MCRs (= MTRRs) constant_tsc: TSC ticks at a constant rate up: smp kernel running on up arch_perfmon: Intel Architectural PerfMon pebs: Precise-Event Based Sampling bts: Branch Trace Store rep_good: rep microcode works well nopl: The NOPL (0F 1F) instructions xtopology: cpu topology enum extensions tsc_reliable: TSC is known to be reliable nonstop_tsc: TSC does not stop in C states extd_apicid: has extended APICID (8 bits) amd_dcm: multi-node processor aperfmperf: APERFMPERF eagerfpu: Non lazy FPU restore nonstop_tsc_s3: TSC doesn't stop in S3 state Intel-defined CPU features, CPUID level 0x00000001 (ecx) See also Wikipedia and table 2-26 in Intel Advanced Vector Extensions Programming Reference pni: SSE-3 ("Prescott New Instructions") pclmulqdq: Perform a Carry-Less Multiplication of Quadword instruction -- accelerator for GCM) dtes64: 64-bit Debug Store monitor: Monitor/Mwait support (Intel SSE3 supplements) ds_cpl: CPL Qual. Debug Store vmx: Hardware virtualization: Intel VMX smx: Safer mode: TXT (TPM support) est: Enhanced SpeedStep tm2: Thermal Monitor 2 ssse3: Supplemental SSE-3 cid: Context ID fma: Fused multiply-add cx16: CMPXCHG16B xtpr: Send Task Priority Messages pdcm: Performance Capabilities pcid: Process Context Identifiers dca: Direct Cache Access sse4_1: SSE-4.1 sse4_2: SSE-4.2 x2apic: x2APIC movbe: Move Data After Swapping Bytes instruction popcnt: Return the Count of Number of Bits Set to 1 instruction (Hamming weight, i.e. bit count) tsc_deadline_timer: Tsc deadline timer aes/aes-ni: Advanced Encryption Standard (New Instructions) xsave: Save Processor Extended States: also provides XGETBY,XRSTOR,XSETBY avx: Advanced Vector Extensions f16c: 16-bit fp conversions (CVT16) rdrand: Read Random Number from hardware random number generator instruction hypervisor: Running on a hypervisor VIA/Cyrix/Centaur-defined CPU features, CPUID level 0xC0000001 rng: Random Number Generator present (xstore) rng_en: Random Number Generator enabled ace: on-CPU crypto (xcrypt) ace_en: on-CPU crypto enabled ace2: Advanced Cryptography Engine v2 ace2_en: ACE v2 enabled phe: PadLock Hash Engine phe_en: PHE enabled pmm: PadLock Montgomery Multiplier pmm_en: PMM enabled More extended AMD flags: CPUID level 0x80000001, ecx lahf_lm: Load AH from Flags (LAHF) and Store AH into Flags (SAHF) in long mode cmp_legacy: If yes HyperThreading not valid svm: "Secure virtual machine": AMD-V extapic: Extended APIC space cr8_legacy: CR8 in 32-bit mode abm: Advanced Bit Manipulation sse4a: SSE-4A misalignsse: Misaligned SSE mode 3dnowprefetch: 3DNow prefetch instructions osvw: OS Visible Workaround ibs: Instruction Based Sampling xop: extended AVX instructions skinit: SKINIT/STGI instructions wdt: Watchdog timer lwp: Light Weight Profiling fma4: 4 operands MAC instructions tce: translation cache extension nodeid_msr: NodeId MSR tbm: Trailing Bit Manipulation topoext: Topology Extensions CPUID leafs perfctr_core: Core Performance Counter Extensions perfctr_nb: NB Performance Counter Extensions perfctr_l2: L2 Performance Counter Extensions Auxiliary flags: Linux defined - For features scattered in various CPUID levels ida: Intel Dynamic Acceleration arat: Always Running APIC Timer cpb: AMD Core Performance Boost epb: IA32_ENERGY_PERF_BIAS support xsaveopt: Optimized Xsave pln: Intel Power Limit Notification pts: Intel Package Thermal Status dts: Digital Thermal Sensor hw_pstate: AMD HW-PState proc_feedback: AMD ProcFeedbackInterface intel_pt: Intel Processor Tracing Virtualization flags: Linux defined tpr_shadow: Intel TPR Shadow vnmi: Intel Virtual NMI flexpriority: Intel FlexPriority ept: Intel Extended Page Table vpid: Intel Virtual Processor ID npt: AMD Nested Page Table support lbrv: AMD LBR Virtualization support svm_lock: AMD SVM locking MSR nrip_save: AMD SVM next_rip save tsc_scale: AMD TSC scaling support vmcb_clean: AMD VMCB clean bits support flushbyasid: AMD flush-by-ASID support decodeassists: AMD Decode Assists support pausefilter: AMD filtered pause intercept pfthreshold: AMD pause filter threshold Intel-defined CPU features, CPUID level 0x00000007:0 (ebx) fsgsbase: {RD/WR}{FS/GS}BASE instructions bmi1: 1st group bit manipulation extensions hle: Hardware Lock Elision avx2: AVX2 instructions smep: Supervisor Mode Execution Protection bmi2: 2nd group bit manipulation extensions erms: Enhanced REP MOVSB/STOSB invpcid: Invalidate Processor Context ID rtm: Restricted Transactional Memory mpx: Memory Protection Extension rdseed: The RDSEED instruction adx: The ADCX and ADOX instructions smap: Supervisor Mode Access Prevention