1CPUID(1) General Commands Manual CPUID(1)
2
6 cpuid - Dump CPUID information for each CPU
7
9 cpuid [options...]
10
12 cpuid dumps detailed information about the CPU(s) gathered from the
13 CPUID instruction, and also determines the exact model of CPU(s) from
14 that information.
15 It dumps all information available from the CPUID instruction. The
17 exact collection of information available varies between manufacturers
18 and processors. The following information is available consistently on
19 all modern CPUs:
20 vendor_id
22 version information (1/eax)
23 miscellaneous (1/ebx)
24 feature information (1/ecx)
25 It also produces synthetic fields based on information from multiple
27 CPUID functions. Currently, the synthetic fields are the exact model
28 of each CPU (but see LIMITATIONS below) as (synth); the multiprocessing
29 characteristics including the number of cores per chip (c) and the num‐
30 ber of hyperthreads per core (t) as (multi-processing synth); and a
31 decoding of the APIC physical ID as (APIC synth).
32 The determination of the model is based on the following information:
34 version information (1/eax), processor type
36 version information (1/eax), family
37 version information (1/eax), model
38 version information (1/eax), stepping id
39 version information (1/eax), extended family
40 version information (1/eax), extended model
41 feature information (1/ecx), virtual machine extensions
42 brand id (1/ebx)
43 brand (0x80000004)
44 cache and TLB information (2)
45 deterministic cache parameters (4/eax), extra processor cores
46 AMD extended brand id (0x80000001/ebx)
47 AMD extended processor signature (0x80000001/eax)
48 Transmeta processor revision ID (0x80860001/ebx & ecx)
49 The determination of the multiprocessing characteristics and decoding
51 of APIC physical ID is based on the following information:
52 feature information (1/edx), hyper-threading / multi-core supported
54 miscellaneous (1/ebx), cpu count
55 deterministic cache parameters (4/eax), extra processor cores on this die
56 x2APIC features / processor topology (0xb)
57 AMD feature flags (0x80000001/ecx)
58 AMD Logical CPU cores (0x80000008/ecx), number of logical CPU cores - 1
59 In addition, a simpler and coarser determination of the CPU is per‐
61 formed using only the information listed above under version informa‐
62 tion (1/eax). It is provided as (simple synth) under version informa‐
63 tion (1/eax). However, it tends to be unable to distinguish between
64 various modern CPUs.
65
67 cpuid accepts the following command line arguments:
68 -1, --one-cpu
70 Display information only for the first CPU. This cuts down on
71 the output on a multiprocessor system, and is useful when cer‐
72 tain that all CPUs are identical.
73 -f FILE, --file=FILE
75 Read raw hex information from FILE instead of from executions
76 of the cpuid instruction.
77 -h, -H, --help
79 Display help information.
80 -i, --inst
82 Use the CPUID instruction. The information it provides is
83 reliable. It is not necessary to be root to use this option.
84 (This option is the default.)
85 -k, --kernel
87 Use the CPUID kernel module. The information does not seem to
88 be reliable on all combinations of CPU type and kernel version.
89 Typically, it is necessary to be root to use this option.
90 -r, --raw
92 Display only raw hex information with no decoding.
93 -v, --version
95 Display cpuid version.
96
98 There are numerous cases where there is no way to distinguish between
99 various CPUs in the (synth) information. In some cases, the sizes of
100 caches, number of cores, brand strings, etc., can be used to distin‐
101 guish multiple CPUs with the same family and model. But there are
102 cases where that information is insufficient. Whenever cpuid is unable
103 to distinguish between multiple CPUs, it will list all known possibili‐
104 ties.
105 If you believe that a certain processor should be distinguishable from
107 another and it isn't, please inform the author of this tool.
108 The (multi-processing synth) information is unreliable on many proces‐
110 sors. It faithfully reports the information provided by the CPUID
111 instruction and decodes it as recommended by the processor manufactur‐
112 ers, but often that information is incorrect. The information seems to
113 indicate the architecture's capabilities, rather than what the particu‐
114 lar chip actually does. In particular, it seems commonplace to claim
115 the presence of multiple hyperthreads when there is only one.
116 Function 0x8000001b appears to be implemented on newer AMD chips, such
118 as Magny-Cours. But AMD's latest CPUID specification is woefully out
119 of date, from around April 2008, and I don't know how to decode this
120 function.
121
123 Information on the CPUID instruction and on specific CPUs is available
124 from the following documents from Intel Corporation
125 <http://www.intel.com/support/processors/index.htm>, with the specified
126 Document Numbers:
127 241618: Intel Processor Identification and the CPUID Instruc‐
129 tion, Application Note 485
130 242480: Pentium Processor Specification Update
131 242689: Pentium Pro Processor Specification Update
132 243326: 60- and 66-MHz Pentium Processor Specification Update
133 243337: Intel Pentium II Processor Specification Update
134 243748: Intel Celeron Processor Specification Update
135 243776: Intel Pentium II Xeon Processor Specification Update
136 243887: Mobile Intel Pentium II Processor Specification Update
137 244444: Mobile Intel Celeron Processor at 466 MHz, 433 MHz, 400
138 MHz, 366 MHz, 333 MHz, 300 MHz, and 266 MHz Specification Update
139 244453: Intel Pentium III Processor Specification Update
140 244460: Intel Pentium III Xeon Processor Specification Update
141 245306: Mobile Intel Pentium III Processor and Mobile Intel Pen‐
142 tium III Processor-M Specification Update
143 245421: Mobile Intel Celeron Processor (0.18u and 0.13u) Speci‐
144 fication Update
145 249199: Intel Pentium 4 Processor Specification Update
146 249678: Intel Xeon Processor Specification Update
147 250721: Mobile Intel Pentium 4 Processor-M Specification Update
148 251309: Mobile Intel Celeron Processor on .13 Micron Process in
149 Micro-FCPGA Package Specification Update
150 252665: Intel Pentium M Processor Specification Update
151 253176: Mobile Intel Pentium 4 Processor with 533 MHz System Bus
152 Specification Update
153 276613: Detecting Multi-Core Processor Topology in an IA-32
154 Platform by Khang Nguyen and Shihjong Kuo
155 290741: Intel Xeon Processor MP Specification Update
156 290749: Intel Celeron Processor in the 478-Pin Package Specifi‐
157 cation Update
158 300303: Intel Celeron M Processor Specification Update
159 302209: Intel Pentium M Processor on 90nm Process with 2-MB L2
160 Cache Specification Update
161 302352: Intel Pentium 4 Processor on 90 nm Process Specification
162 Update
163 302354: Intel Celeron D Processor 3xx Sequence Specification
164 Update
165 302402: Intel Xeon Processor with 800 MHz System Bus
166 302441: Mobile Intel Pentium 4 Processor supporting Hyper-
167 Threading Technology on 90-nm process technology Specification
168 Update
169 306752: 64-bit Intel Xeon Processor MP with 1 MB L2 Cache Speci‐
170 fication Update
171 306757: 64-bit Intel Xeon Processor MP with up to 8 MB L3 Cache
172 Specification Update
173 306832: Intel Pentium Processor Extreme Edition and Intel Pen‐
174 tium D Processor Specification Update
175 309159: Dual-Core Intel Xeon Processor 2.80 GHz Specification
176 Update
177 309222: Intel Core Duo Processor and Intel Core Solo Processor
178 on 65 nm Process Specification Update
179 309627: Dual-Core Intel Xeon Processor 7000 Sequence Specifica‐
180 tion Update
181 311827: Intel Celeron D Processor 300 Sequence Specification
182 Update
183 313065: Dual-Core Intel Xeon Processor 5000 Series Specification
184 Update
185 313279: Intel Core 2 Extreme Processor X6800 and Intel Core 2
186 Duo Desktop Processor E6000 Sequence Specification Update
187 313356: Dual-Core Intel Xeon Processor 5100 Series Specification
188 Update
189 314554: Dual-Core Intel Xeon Processor 7100 Series Specification
190 Update
191 314916: Dual-Core Intel Xeon Processor 3000 Series Specification
192 Update
193 313515: Intel Pentium Dual-Core Processor Specification Update
194 316134: Quad-Core Intel Xeon Processor 3200 Series Specification
195 Update
196 316964: Intel Celeron Processor 400 Series Specification Update
197 316982: Intel Pentium Dual-Core Desktop Processor E2000 Series
198 Specification Update
199 317667: Intel Celeron Processor 500 Series Specification Update
200 318081: Intel Xeon Processor 7200 and 7300 Series Specification
201 Update
202 318547: Intel Celeron Processor 200 Sequence Specification
203 Update
204 318585: Intel Xeon Processor 5400 Series Specification Update
205 318586: Intel Xeon Processor 5200 Series Specification Update
206 318727: Intel Core 2 Extreme Processor QX9000 Series and Intel
207 Core 2 Quad Processor Q9000, Q9000S, Q8000, Q8000S Series Speci‐
208 fication Update
209 318733: Intel Core 2 Duo Processor E8000 and E7000 Series Speci‐
210 fication Update
211 318915: Intel Core 2 Duo Processor and Intel Core 2 Extreme Pro‐
212 cessor on 45-nm Process Specification Update
213 318925: Intel Celeron Dual-Core Processor E1000 Series Specifi‐
214 cation Update
215 319006: Dual-Core Intel Xeon Processor 3100 Series Specification
216 Update
217 319007: Quad-Core Intel Xeon Processor 3300 Series Specification
218 Update
219 319129: Intel Core 2 Extreme Processor QX9775 Specification
220 Update
221 319536: Intel Atom Processor Z5xx Series Specification Update
222 319735: Intel Celeron Dual-Core Processor T1x00 Series Specifi‐
223 cation Update
224 319978: Intel Atom Processor 200 Series Specification Update
225 320047: Intel Atom Processor N270 Series Specification Update
226 320121: Intel Core 2 Extreme Quad-Core Mobile Processor, Intel
227 Core 2 Quad Mobile Processor, Intel Core 2 Extreme Mobile Pro‐
228 cessor, Intel Core 2 Duo Mobile Processor, Intel Core 2 Solo
229 Mobile Processor and Intel Celeron Processor on 45-nm Process
230 Specification Update
231 320257: Intel EP80579 Integrated Processor Product Line Specifi‐
232 cation Update
233 320336: Intel Xeon Processor 7400 Series Specification Update
234 320468: Intel Pentium Dual-Core E6000 and E5000 Series Specifi‐
235 cation Update
236 320529: Intel Atom Processor 300 Series Specification Update
237 320767: Intel Core i7-900 Mobile Processor Extreme Edition
238 Series, Intel Core i7-800 and i7-700 Mobile Processor Series
239 Specification Update
240 320836: Intel Core i7-900 Desktop Processor Extreme Edition
241 Series and Intel Core i7-900 Desktop Processor Series Specifica‐
242 tion Update
243 321324: Intel Xeon Processor 5500 Series Specification Update
244 321333: Intel Xeon Processor 3500 Series Specification Update
245 322166: Intel Core i7-800 and i5-700 Desktop Processor Series
246 Specification Update
247 322373: Intel Xeon Processor 3400 Series Specification Update
248 322568: Intel Celeron Processor E3x00 Series Specification
249 Update
250 322849: Intel Atom Processor N400 Series Specification Update
251 322861: Intel Atom Processor D400 Series (Single Core) Specifi‐
252 cation Update
253 322862: Intel Atom Processor D500 Series (Dual Core) Specifica‐
254 tion Update
255 322814: Intel Core i7-600, i5-500, i5-400 and i3-300 Mobile Pro‐
256 cessor Series Specification Update
257 322911: Intel Core i5-600, i3-500 Desktop Processor Series and
258 Intel Pentium Processor G6950 Specification Update
259 323056: Intel Xeon Processor L3406 Specification Update
260 323179: Intel Core i7-660UE, i7-620LE/UE, i7-610E, i5-520E,
261 i3-330E and Intel Celeron Processor P4505, U3405 Series
262 Datasheet Addendum Specification Update
263 323105: Intel Xeon Processor C5500/C3500 Series Specification
264 Update
265 323254: Intel Core i7-900 Desktop Processor Extreme Edition
266 Series and Intel Core i7-900 Desktop Processor Series on 32-nm
267 Process Specification Update
268 323338: Intel Xeon Processor 3600 Series Specification Update
269 323344: Intel Xeon Processor 7500 Series Specification Update
270 323372: Intel Xeon Processor 5600 Series Specification Update
271 323874: Intel Pentium P6000 and U5000 Mobile Processor Series
272 Specification Update
273 324341: Intel Atom Processor N500 Series Specification Update
274 Intel 64 Architecture Processor Topology Enumeration (Whitepa‐
275 per)
276 324456: Intel Celeron Mobile Processor P4000 and U3000 Series
277 Specification Update
278 324643: 2nd Generation Intel Core Processor Family Desktop Spec‐
279 ification Update
280 324827: 2nd Generation Intel Core Processor Family Mobile Speci‐
281 fication Update
282 Information on the CPUID instruction and on specific CPUs is available
284 from the following documents from Advanced Micro Devices, Inc.
285 <http://www.amd.com/us-en/Processors/TechnicalResources>, with the
286 specified Publication Numbers:
287 20734: AMD Processor Recognition Application Note
289 21266: AMD-K6 Processor Revision Guide Model 6
290 21641: AMD-K6-2 Processor Revision Guide Model 8
291 21846: AMD-K6 Processor Revision Guide Model 7
292 22473: AMD-K6-III Processor Revision Guide Model 9
293 23614: AMD Athlon Processor Model 4 Revision Guide
294 23865: AMD Duron Processor Model 3 Revision Guide
295 24332: AMD Athlon Processor Model 6 Revision Guide
296 24806: AMD Duron Processor Model 7 Revision Guide
297 25481: CPUID Specification
298 25703: AMD Athlon Processor Model 8 Revision Guide
299 25759: Revision Guide for AMD Athlon 64 and AMD Opteron Proces‐
300 sors
301 26094: BIOS and Kernel Developer's Guide for AMD Athlon 64 and
302 AMD Opteron Processors
303 27532: AMD Athlon Processor Model 10 Revision Guide
304 31177H: AMD Geode NX Processors Data Book
305 31610: Revision Guide for AMD NPT Family 0Fh Processors
306 33234F: AMD Geode LX Processors Data Book
307 41322: Revision Guide for AMD Family 10h Processors
308 41788: Revision Guide for AMD Family 11h Processors
309 Information on the CPUID instruction and on specific CPUs is available
311 from the following documents from Transmeta Corporation
312 <http://www.transmeta.com/crusoe_docs/Crusoe_CPUID_5-7-02.pdf>:
313 Processor Recognition, 2002/05/07
315 Also, information is available from the following web sites:
317 <http://www.sandpile.org/ia32/cpuid.htm>
319 <http://en.wikipedia.org/wiki/List_of_Intel_microprocessors>
320 <http://en.wikipedia.org/wiki/List_of_AMD_microprocessors>
321 <http://en.wikipedia.org/wiki/Category:X86_microprocessors>
322
324 Todd Allen <cpuid@etallen.com>
32520110305 5 Mar 2011 CPUID(1)