CPU Benchmarks

CPUBenchmarks

This page displays the iteration times for version 21 of the program for a wide variety of CPUs and exponents. All iteration times are in seconds. See the end of this page for how you can send in the benchmarks for your machine. Where more than one user has reported timings for a given CPU, anomalous timings are discarded and the rest are averaged. The more timings that are sent in the more accurate this chart will be. So please send in your timings even if your machine is listed below.

The time it takes to test one exponent is the exponent being tested multiplied by the iteration time. For example, you own a 300 MHz Celeron machine and are considering running first-time tests, if the PrimeNet server shows that the smallest available first-time exponents are around 15,800,000, find the column marked 15.3M to 17.85M and the row containing your CPU to find a per-iteration speed of 0.707 seconds. The time it takes to run one first-time test is 15,800,000 * 0.707 seconds, or 11,170,600 seconds, or (divide by 86,400) 129 days.

If the above calculations are too cumbersome, use the form below. Enter the exponent you are thinking of testing (first-time tests are around 15,800,000, double-checks are about 8,000,000, and ten million digit primes capable of claiming the EFF prize are above 33,219,280). Enter your CPU type and speed, and how many hours a day your computer is on. The estimated test time and number of decimal digits in the Mersenne number will be displayed.

This table is for CPUs supporting the SSE2 instruction set. While faster, the SSE2 instructions have a little less precision making the exponent ranges slightly lower.

CPU					Iteration Times For Various Exponent Ranges and FFT sizes
Type	Speed (MHz)	Memory Speed	L2 Cache Size	L2 Cache Speed	4.555M to 5.185M (256K)	5.185M to 6.465M (320K)	6.465M to 7.69M (384K)	7.69M to 8.97M (448K)	8.97M to 10.24M (512K)	10.24M to 12.72M (640K)	12.72M to 15.16M (768K)	15.16M to 17.66M (896K)	17.66M to 20.18M (1024K)	20.18M to 25.09M (1280K)	25.09M to 29.92M (1536K)	29.92M to 34.86M (1792K)
P4	2400	133DDR	512	Full	0.011	0.014	0.017	0.020	0.022	0.029	0.036	0.042	0.046	0.065	0.084	0.103
P4	2200	PC800	512	Full	0.011	0.014	0.018	0.021	0.024	0.031	0.037	0.046	0.050	0.072	0.089	0.111
P4	2000	PC800	512	Full	0.012	0.016	0.019	0.023	0.026	0.034	0.041	0.050	0.055	0.078	0.096	0.120
P4	2000	133DDR	512	Full	0.012	0.016	0.020	0.024	0.027	0.035	0.042	0.051	0.056	0.080	0.098	0.120
P4	2000	PC800	256	Full	0.013	0.017	0.020	0.025	0.027	0.036	0.044	0.054	0.059	0.083	0.104	0.134
P4	1900	PC800	256	Full	0.013	0.018	0.021	0.026	0.029	0.038	0.046	0.057	0.062	0.086	0.106	0.131
P4	1800	PC800	512	Full	0.013	0.018	0.021	0.026	0.029	0.037	0.045	0.056	0.060	0.086	0.107	0.131
P4	1800	PC800	256	Full	0.014	0.018	0.022	0.027	0.030	0.039	0.048	0.059	0.064	0.091	0.113	0.144
P4	1800	133DDR	256	Full	0.014	0.018	0.022	0.026	0.030	0.039	0.047	0.059	0.063	0.090	0.115	0.143
P4	1800	133SDRAM	256	Full	0.017	0.021	0.025	0.030	0.034	0.044	0.054	0.066	0.071	0.101	0.126	0.171
P4	1700	PC800	256	Full	0.014	0.019	0.023	0.028	0.032	0.041	0.050	0.063	0.067	0.096	0.120	0.150
P4	1700	133DDR	256	Full	0.015	0.020	0.024	0.029	0.033	0.043	0.052	0.065	0.070	0.099	0.124	0.163
P4	1700	133SDRAM	256	Full	0.018	0.023	0.027	0.032	0.036	0.048	0.059	0.072	0.079	0.110	0.137	0.185
P4	1600	PC800	512	Full	0.015	0.020	0.024	0.029	0.032	0.042	0.051	0.062	0.067	0.096	0.118	0.145
P4	1600	PC600	512	Full	0.015	0.020	0.024	0.029	0.033	0.042	0.051	0.063	0.068	0.096	0.119	0.148
P4	1600	PC800	256	Full	0.015	0.020	0.025	0.030	0.033	0.044	0.053	0.066	0.071	0.101	0.125	0.159
P4	1600	133DDR	256	Full	0.017	0.023	0.028	0.033	0.037	0.048	0.059	0.073	0.079	0.114	-	-
P4	1600	100SDRAM	256	Full	0.018	0.023	0.027	0.033	0.037	0.049	0.059	0.074	0.081	0.115	0.143	0.178
P4	1500	PC800	256	Full	0.016	0.022	0.026	0.032	0.036	0.046	0.056	0.070	0.076	0.108	0.134	0.170
P4	1500	133SDRAM	256	Full	0.019	0.024	0.030	0.035	0.040	0.052	0.063	0.079	0.087	0.120	0.154	0.196
P4	1400	PC800	256	Full	0.017	0.023	0.028	0.034	0.038	0.050	0.060	0.075	0.081	0.116	0.145	0.180
P4	1400	PC600	256	Full	0.018	0.024	0.029	0.035	0.039	0.052	0.063	0.079	0.086	0.119	0.148	0.185
P4	1300	PC800	256	Full	0.019	0.025	0.030	0.037	0.041	0.054	0.066	0.082	0.088	0.125	0.153	0.190
Celeron	1700	166DDR	128	Full	0.016	0.022	0.026	0.032	0.036	0.053	0.063	0.092	0.116	0.199	0.254	0.340
Celeron	1700	133DDR	128	Full	0.016	0.024	0.029	0.034	0.038	0.054	0.064	0.094	0.113	0.197	0.262	0.342

This table is for CPUs not supporting the SSE2 instruction set.

CPU					Iteration Times For Various Exponent Ranges and FFT sizes
Type	Speed (MHz)	Memory Speed	L2 Cache Size	L2 Cache Speed	4.598M to 5.255M (256K)	5.255M to 6.52M (320K)	6.52M to 7.76M (384K)	7.76M to 9.04M (448K)	9.04M to 10.33M (512K)	10.33M to 12.83M (640K)	12.83M to 15.3M (768K)	15.3M to 17.85M (896K)	17.85M to 20.4M (1024K)	20.4M to 25.35M (1280K)	25.35M to 30.15M (1536K)	30.15M to 35.1M (1792K)
AthlonXP 2100+	1733	133DDR	256	Full	0.026	0.033	0.041	0.047	0.052	0.066	0.081	0.095	0.108	0.142	0.175	0.208
AthlonXP 2000+	1667	133DDR	256	Full	0.025	0.033	0.042	0.047	0.052	0.067	0.082	0.096	0.111	0.146	0.177	0.213
AthlonXP 1900+	1600	133DDR	256	Full	0.024	0.031	0.040	0.044	0.049	0.063	0.077	0.090	0.103	0.136	0.164	0.197
AthlonXP 1800+	1533	166DDR	256	Full	0.021	0.027	0.035	0.039	0.044	0.056	0.069	0.081	0.092	0.122	0.148	0.178
AthlonXP 1800+	1533	133DDR	256	Full	0.024	0.031	0.040	0.044	0.049	0.063	0.078	0.091	0.104	0.137	0.165	0.199
AthlonXP 1700+	1466	133DDR	256	Full	0.025	0.032	0.042	0.046	0.051	0.067	0.081	0.096	0.109	0.143	0.173	0.209
AthlonXP 1600+	1400	133DDR	256	Full	0.026	0.033	0.044	0.048	0.053	0.069	0.084	0.099	0.112	0.148	0.179	0.216
AthlonXP 1600+	1400	133	256	Full	0.035	0.045	0.056	0.064	0.071	0.090	0.110	0.130	0.146	0.194	0.233	0.281
AthlonXP 1500+	1333	133DDR	256	Full	0.027	0.034	0.046	0.050	0.055	0.072	0.087	0.103	0.117	0.154	0.185	0.224
Tbird	1400	133DDR	256	Full	0.027	0.034	0.044	0.051	0.055	0.073	0.088	0.103	0.119	0.157	0.189	0.224
Tbird	1400	133	256	Full	0.032	0.040	0.052	0.057	0.063	0.083	0.101	0.119	0.135	0.178	0.214	0.256
Tbird	1333	133DDR	256	Full	0.029	0.036	0.044	0.053	0.057	0.076	0.093	0.109	0.123	0.162	0.196	0.235
Tbird	1333	133	256	Full	0.035	0.045	0.058	0.065	0.072	0.093	0.113	0.133	0.155	0.202	0.244	0.291
Tbird	1333	100	256	Full	0.037	0.047	0.061	0.068	0.075	0.095	0.118	0.137	0.158	0.210	0.251	0.302
Tbird	1200	133DDR	256	Full	0.031	0.039	0.051	0.058	0.063	0.083	0.102	0.119	0.135	0.180	0.216	0.258
Tbird	1200	133	256	Full	0.035	0.044	0.056	0.065	0.070	0.092	0.112	0.131	0.150	0.197	0.236	0.284
Tbird	1100	133	256	Full	0.039	0.050	0.065	0.072	0.079	0.103	0.128	0.149	0.172	0.225	0.270	0.324
Tbird	1000	133DDR	256	Full	0.036	0.046	0.059	0.067	0.073	0.097	0.119	0.138	0.159	0.208	0.251	0.300
Tbird	1000	133	256	Full	0.039	0.048	0.065	0.071	0.077	0.102	0.125	0.147	0.168	0.221	0.265	0.319
Tbird	900	133	256	Full	0.044	0.055	0.072	0.080	0.088	0.116	0.142	0.166	0.190	0.249	0.300	0.361
Tbird	900	100	256	Full	0.045	0.057	0.073	0.083	0.091	0.120	0.145	0.171	0.195	0.258	0.310	0.370
Athlon	900	100	256	Full	0.047	0.059	0.076	0.086	0.094	0.124	0.150	0.177	0.201	0.268	0.325	0.386
Tbird	800	133	256	Full	0.046	0.058	0.076	0.086	0.093	0.124	0.152	0.179	0.202	0.267	0.322	0.389
Athlon	800	100	512	Half	0.050	0.063	0.082	0.094	0.102	0.138	0.168	0.198	0.228	0.300	0.364	0.436
Tbird	700	100	256	Full	0.051	0.064	0.086	0.094	0.102	0.137	0.167	0.196	0.223	0.293	0.353	0.426
Athlon	700	100	512	Half	0.053	0.068	0.094	0.100	0.109	0.147	0.182	0.215	0.246	0.322	0.392	0.475
Athlon	650	100	512	Half	0.058	0.073	0.096	0.109	0.119	0.160	0.196	0.232	0.263	0.346	0.420	0.509
Athlon	600	100	512	Half	0.064	0.082	0.107	0.120	0.132	0.182	0.215	0.272	0.298	0.382	0.473	0.607
Athlon	550	100	512	Half	0.066	0.084	0.115	0.124	0.135	0.181	0.221	0.262	0.299	0.392	0.477	0.574
Athlon	500	100	512	Half	0.072	0.092	0.128	0.136	0.149	0.200	0.245	0.290	0.329	0.432	0.521	0.630
Duron	1000	100DDR	64	Full	0.040	0.051	0.066	0.074	0.081	0.107	0.133	0.160	0.184	0.257	0.318	0.388
Duron	950	133	64	Full	0.044	0.056	0.072	0.081	0.089	0.119	0.147	0.176	0.205	0.282	0.348	0.426
Duron	900	133	64	Full	0.041	0.052	0.069	0.076	0.083	0.111	0.138	0.165	0.190	0.260	0.321	0.393
Duron	850	100	64	Full	0.051	0.065	0.083	0.094	0.104	0.138	0.169	0.203	0.235	0.320	0.395	0.484
Duron	800	100	64	Full	0.050	0.063	0.080	0.091	0.100	0.134	0.165	0.197	0.228	0.311	0.383	0.468
Duron	750	133	64	Full	0.052	0.065	0.087	0.095	0.104	0.139	0.172	0.205	0.237	0.321	0.394	0.481
Duron	700	133	64	Full	0.054	0.069	0.088	0.100	0.109	0.146	0.181	0.215	0.249	0.337	0.413	0.504
Duron	700	100	64	Full	0.057	0.072	0.097	0.107	0.116	0.157	0.192	0.232	0.269	0.365	0.447	0.549
Duron	600	100	64	Full	0.063	0.080	0.107	0.117	0.128	0.171	0.211	0.252	0.289	0.394	0.485	0.593
P-III	1266	133	512	Full	0.040	0.052	0.063	0.076	0.087	0.113	0.137	0.162	0.187	0.242	0.286	0.340
P-III	1133	133	512	Full	0.049	0.064	0.078	0.092	0.105	0.138	0.173	0.198	0.235	0.299	0.361	0.430
P-III	1000	133	256	Full	0.050	0.064	0.078	0.092	0.107	0.139	0.165	0.193	0.222	0.289	0.348	0.416
P-III	933	PC800	256	Full	0.049	0.063	0.077	0.090	0.101	0.133	0.159	0.189	0.213	0.277	0.335	0.404
P-III	933	133	256	Full	0.054	0.072	0.087	0.103	0.116	0.150	0.183	0.216	0.246	0.315	0.382	0.454
P-III	866	133	256	Full	0.050	0.064	0.079	0.092	0.103	0.135	0.162	0.193	0.218	0.285	0.343	0.417
P-III	866	PC800	256	Full	0.053	0.067	0.083	0.096	0.108	0.143	0.170	0.202	0.228	0.297	0.358	0.433
P-III	850	100	256	Full	0.060	0.077	0.093	0.110	0.124	0.161	0.195	0.230	0.263	0.338	0.409	0.491
P-III	800	133	256	Full	0.055	0.070	0.087	0.101	0.112	0.150	0.178	0.211	0.238	0.310	0.375	0.454
P-III	800	100	256	Full	0.062	0.080	0.098	0.116	0.129	0.168	0.203	0.239	0.274	0.355	0.438	0.521
P-III	750	100	256	Full	0.066	0.085	0.103	0.122	0.138	0.180	0.219	0.257	0.296	0.381	0.460	0.553
P-III	733	133	256	Full	0.062	0.079	0.097	0.113	0.126	0.167	0.199	0.236	0.265	0.348	0.425	0.511
P-III	700	100	256	Full	0.070	0.090	0.110	0.129	0.145	0.189	0.229	0.271	0.308	0.398	0.480	0.577
P-III	650	100	256	Full	0.071	0.092	0.111	0.131	0.146	0.190	0.230	0.270	0.308	0.398	0.477	0.569
P-III	600	100	256	Full	0.072	0.091	0.112	0.130	0.145	0.193	0.231	0.274	0.309	0.397	0.480	0.581
P-III	600	100	512	Half	0.080	0.103	0.126	0.149	0.167	0.226	0.268	0.318	0.357	0.458	0.550	0.660
P-III	500	100	256	Full	0.086	0.111	0.136	0.157	0.176	0.234	0.280	0.332	0.375	0.484	0.585	0.708
P-III	500	100	512	Half	0.089	0.114	0.140	0.163	0.181	0.244	0.291	0.345	0.389	0.500	0.600	0.720
P-III	450	100	512	Half	0.099	0.126	0.155	0.181	0.201	0.271	0.323	0.383	0.432	0.555	0.665	0.802
P-II	450	100	512	Half	0.122	0.160	0.196	0.234	0.262	0.344	0.421	0.498	0.558	0.720	0.864	1.035
P-II	400	100	512	Half	0.128	0.169	0.207	0.247	0.276	0.365	0.444	0.529	0.593	0.799	0.952	1.098
P-II	366	66	512	Half	0.159	0.208	0.253	0.304	0.337	0.442	0.537	0.639	0.710	-	-	-
P-II	366	66	256	Full	0.155	0.204	0.259	0.309	0.343	0.447	0.551	0.650	0.731	0.979	1.166	1.405
P-II	350	100	512	Half	0.144	0.189	0.232	0.278	0.309	0.407	0.499	0.592	0.661	0.857	1.031	1.233
P-II	333	66	512	Half	0.173	0.227	0.278	0.332	0.371	0.488	0.593	0.700	0.786	1.012	1.213	1.450
P-II	300	100	512	Half	0.163	0.213	0.261	0.314	0.349	0.459	0.563	0.667	0.744	-	-	-
P-II	300	66	512	Half	0.174	0.229	0.279	0.335	0.373	0.493	0.600	0.712	0.794	1.028	1.231	1.474
P-II	266	66	512	Half	0.198	0.262	0.320	0.382	0.427	0.561	0.686	0.808	0.907	1.180	1.415	1.688
P-II	233	66	512	Half	0.221	0.289	0.377	0.422	0.470	0.621	0.757	0.895	1.001	-	-	-
Celeron	1200	100	256	Full	0.052	0.067	0.082	0.097	0.110	0.143	0.177	0.209	0.240	0.308	0.372	0.446
Celeron	1100	100	256	Full	0.055	0.070	0.086	0.102	0.116	0.154	0.188	0.220	0.256	0.330	0.408	0.482
Celeron	900	100	128	Full	0.059	0.076	0.092	0.109	0.123	0.161	0.197	0.231	0.266	0.342	0.422	0.509
Celeron	800	100	128	Full	0.063	0.081	0.099	0.118	0.133	0.175	0.212	0.249	0.284	0.370	0.458	0.554
Celeron	733	66	128	Full	0.087	0.113	0.138	0.165	0.189	0.246	0.301	0.358	0.407	0.524	0.647	0.775
Celeron	700	66	128	Full	0.080	0.101	0.123	0.147	0.166	0.218	0.265	0.316	0.359	0.501	0.615	0.743
Celeron	600	66	128	Full	0.084	0.114	0.130	0.165	0.185	0.244	0.295	0.331	0.399	0.508	0.590	0.750
Celeron	550	100	128	Full	0.098	0.137	0.163	0.202	0.192	0.259	0.313	0.378	0.427	0.550	0.667	0.808
Celeron	533	66	128	Full	0.121	0.159	0.193	0.231	0.257	0.343	0.414	0.495	0.559	0.732	0.888	1.072
Celeron	500	66	128	Full	0.126	0.165	0.201	0.241	0.268	0.355	0.430	0.513	0.578	0.758	0.930	1.123
Celeron	466	66	128	Full	0.133	0.172	0.211	0.253	0.282	0.370	0.450	0.534	0.600	-	-	-
Celeron	433	66	128	Full	0.139	0.182	0.221	0.264	0.294	0.387	0.470	0.557	0.628	0.823	1.000	1.208
Celeron	400	66	128	Full	0.148	0.194	0.235	0.282	0.315	0.413	0.502	0.593	0.669	0.917	1.116	1.342
Celeron	366	66	128	Full	0.147	0.193	0.234	0.281	0.311	0.411	0.497	0.594	0.661	0.867	1.047	1.263
Celeron	333	66	128	Full	0.163	0.215	0.259	0.311	0.345	0.457	0.557	0.658	0.738	-	-	-
Celeron	300	66	128	Full	0.176	0.231	0.281	0.333	0.369	0.489	0.591	0.707	0.786	-	-	-
Celeron	266	66	none	n/a	0.200	0.262	0.323	0.387	0.435	0.573	0.704	0.830	0.940	1.228	1.468	1.753
PPro	200	66	256	Full	0.272	0.350	0.431	0.504	0.571	0.744	0.914	1.058	1.210	1.749	2.131	2.531
PPro	180	60	256	Full	0.380	0.482	0.593	0.690	0.785	0.977	1.181	1.349	1.537	-	-	-
Pent.MMX	233	66	512	Bus	0.293	0.386	0.469	0.566	0.637	0.843	1.019	1.218	1.366	1.789	2.148	2.564
Pent. MMX	200	66	512	Bus	0.324	0.424	0.513	0.618	0.689	0.916	1.104	1.324	1.479	1.967	2.381	2.835
Pent.MMX	166	66	1024	Bus	0.353	0.468	0.565	0.688	0.763	1.024	1.227	1.475	1.644	-	-	-
Pent.MMX	166	66	256	Bus	0.372	0.490	0.594	0.719	0.802	1.069	1.286	1.542	1.721	2.259	2.699	3.236
Pentium	200	66	512	Bus	0.342	0.442	0.533	0.642	0.718	0.954	1.146	1.372	1.535	1.973	2.353	-
Pentium	200	66	256	Bus	0.376	0.482	0.580	0.694	0.780	1.029	1.243	1.481	1.670	-	-	-
Pentium	166	66	256	Bus	0.396	0.510	0.614	0.739	0.827	1.102	1.328	1.975	2.218	-	-	-
Pentium	133	66	256	Bus	0.456	0.592	0.709	0.854	0.950	1.266	1.521	1.824	2.039	2.853	3.436	4.132
Pentium	100	66	512	Bus	0.577	0.748	0.901	1.087	1.201	1.632	1.954	2.346	2.599	3.329	3.992	4.775
Pentium	100	66	256	Bus	0.637	0.821	0.988	1.188	1.328	1.773	2.139	2.558	2.866	3.713	4.459	5.354
Pentium	75	50	none	n/a	0.836	1.091	1.315	1.567	1.763	2.349	2.834	3.362	3.785	-	-	-
Pentium	66	66	256	Bus	0.935	1.207	1.453	1.745	1.949	2.602	3.130	3.741	4.181	-	-	-
Pentium	60	60	256	Bus	1.021	1.325	1.591	1.910	2.124	2.837	3.408	4.077	4.560	-	-	-
VIAC3	866	133	64	Full	0.197	0.258	0.308	0.374	0.408	0.541	0.642	0.779	0.859	1.133	1.382	1.693
VIAC3	800	?	?	?	0.414	0.552	0.656	0.798	0.885	1.172	1.396	1.709	1.886	2.496	3.018	3.678
VIAC3	600	100	64	Full	0.60	0.82	0.99	1.20	1.32	1.81	2.19	2.69	2.91	4.01	4.94	6.37
Crusoe	600	100	512	Full	0.130	0.170	0.200	0.240	0.280	0.360	0.440	0.520	0.591	0.761	0.912	1.101
AMDK6-2	500	100	1024	Bus	0.289	0.385	0.465	0.560	0.620	0.824	1.004	1.213	1.351	-	-	-
AMDK6-3	450	100	256	Full	0.299	0.400	0.483	0.585	0.649	0.860	1.043	1.257	1.392	1.813	2.167	2.600
AMD K6-3	400	100	256	Full	0.328	0.439	0.527	0.635	0.701	0.924	1.113	1.339	1.485	2.040	2.453	2.960
AMD K6-3	400	66	256	Full	0.419	0.539	0.659	0.788	0.883	1.165	1.415	1.685	1.894	-	-	-
AMDK6-2	400	100	1024	Bus	0.331	0.442	0.529	0.640	0.708	0.949	1.149	1.396	1.543	2.004	2.392	2.873
AMDK6-2	400	100	none	n/a	0.395	0.548	0.644	0.762	0.841	1.135	1.386	1.677	1.877	2.424	2.898	3.468
AMDK6-2	350	100	?	Bus	0.399	0.525	0.631	0.761	0.839	1.125	1.359	1.644	1.822	2.365	2.823	3.392
AMDK6-2	333	66	512	Bus	0.434	0.575	0.693	0.834	0.924	1.235	1.496	1.796	2.016	-	-	-
AMDK6-2	300	100	??	n/a	0.491	0.653	0.794	0.951	1.052	1.390	1.674	2.035	2.254	-	-	-
AMDK6-2	233	66	1024	Bus	0.648	0.863	1.034	1.258	1.388	1.853	2.457	2.727	2.976	4.043	4.698	5.635
AMDK6	200	66	512	Bus	0.750	1.001	1.202	1.449	1.596	2.113	2.541	3.080	3.414	-	-	-
AMDK5	100	66	512	Bus	1.242	1.631	1.953	2.363	2.583	3.502	4.175	5.063	5.552	7.194	8.573	10.364
AMDK5	75	50	512	Bus	1.666	2.201	2.613	3.168	3.475	4.710	5.596	6.793	7.439	9.686	11.517	13.896
IDTWinChip	180	60	512	Bus	1.32	1.75	2.09	2.58	2.80	3.79	4.50	5.49	6.04	7.90	9.44	11.43
Via C3	700	100	64	Full	0.230	0.310	0.361	0.450	0.490	0.641	0.771	0.941	1.041	1.362	1.663	2.043
Cyrix M2	225	75	512	Bus	0.99	1.32	1.59	1.97	2.14	2.91	3.46	4.23	4.56	-	-	-
Cyrix 6x86	150	50	512	Bus	1.880	2.477	2.952	3.610	3.914	5.283	6.337	7.655	8.351	-	-	-
Cyrix 6x86	100	50	256	Bus	2.8	3.7	4.4	5.4	5.8	7.8	9.2	11.4	12.2	-	-	-
Cyrix 5x86	120	60	256	Bus	2.63	3.51	4.17	5.16	5.55	7.41	8.84	10.8	11.8	-	-	-
486	133	33	256	Bus	3.535	4.687	5.628	6.870	7.451	9.944	11.89	14.46	15.76	-	-	-
486	66	33	256	Bus	7.850	10.88	12.96	15.71	17.19	23.51	27.02	31.41	34.43	-	-	-
486	33	33	128	Bus	12.61	16.77	20.01	24.50	26.39	35.43	42.29	52.00	56.00	74.00	-	-
486SLC2+FPU	66	33	none	n/a	44.67	60.09	71.54	87.24	94.07	127.54	152.23	185.22	207.39	-	-	-
486SLC+FPU	33	33	none	n/a	51.72	68.69	81.97	99.67	108.05	146.23	174.72	211.77	237.84	-	-	-
386DX+FPU	40	40	256	Bus	34.53	45.68	54.65	66.34	71.95	97.16	116.18	140.90	161.64	-	-	-
386DX+FPU	25	25	128	Bus	58.05	76.78	91.78	111.60	121.16	167.09	262.66	412.05	525.91	755.23	946.42	1188.37
386SX+FPU	20	20	none	n/a	135.18	183.07	221.24	266.85	292.76	396.81	459.02	590.65	681.68	-	-	-

I have also compiled benchmarks on many overclocked machines. Also available are benchmarks for version 20 of the program.

Benchmarking your machine

I need data for Intel-compatible CPUs only. You must be running version 21 or later. If you are currently testing an exponent, choose Test/Stop. Then choose Options/Benchmark. Finally, choose Test/Continue to resume testing your exponent.

Email to me the timings (saved in results.txt) along with the following data (if unsure of a value that's OK).

    CPU type:      Pentium, PPro, P-II, P-III, Xeon, Celeron, K6, Athlon, P4, etc.
    CPU Speed:     in megahertz
    L2 cache size: in KB
    L2 cache speed:as a multiplier of CPU speed
    Memory Type / Bus Speed:
                   66, 100, or 133 MHz SDRAM, PC1600 DDR, PC800 RDRAM, etc.
    OS:            Windows 95, 98, NT, 2000, Linux, etc.
    Notes:         Other special information you think I might need to know.

Last updated: July 26, 2002

A little history of Intel's Pentium II

Before we get into the details of the SL2W8, we should first recap the history of the PII 300.

Die Size
A few months after the first launch of Intel's Pentium II as 233 and 266 MHz version in Q2 1997, Intel released the PII 300. At this time the Pentium II was manufactured using the .35-micron technology. The code name of the Pentium II chip from this time was 'Klamath'. At the beginning of 1998, Intel introduced the 333 MHz PII, followed later by the 350, 400 and 450 MHz version. The 333 MHz PII and up was not using the older .35-micron Klamath core anymore, but the new 'Deschutes' core, a chip produced using the .25-micron technology. The 'Deschutes' core is not much different to Klamath in terms of its functionality, both chips are Pentium II chips and perform equally. The difference is subtler and is also not simply defined by the core. Klamath has a larger die size, due to the .35-micron technology, which you can see by having a look at the chips.
Klamath
PII 233 - 300
Deschutes
PII 333 - 400

PII 450
Core Voltage
The next difference between the chips is the voltage they are running at, the Klamath is using 2.2 V, the Deschutes runs at only 2 V. The die size and the voltage difference are both responsible for the difference in heat production. Klamath becomes a lot hotter than Deschutes, making overclocking of Klamath a lot harder than overclocking Deschutes.
Tag RAM Chip 82459
That is not the only difference between older and new PII CPUs, there is also the L2 cache controller. As you all know, the Pentium II has got a L2 cache within its cartridge, running at half the processor clock. This L2 cache needs a L2 cache controller, because Intel did not include one into the Pentium II core. One of the important things about L2 cache controllers is its cacheable area. The combined L2 cache controller / tag RAM chip used together with Klamath chips on PII 233 - 300 MHz used to be the '82459AB'. This chip could only cache up to 512 MB of memory, so that those Pentium II CPUs could not run with more memory than 512 MB. The first Pentium II 333 CPUs came with the '82459AC' L2 cache controller/tag RAM chip, which can run at higher clocks, but it is still only able to cache 512 MB. Later the PII 333 and all faster PII CPUs (350,400,450 MHz) were equipped with the '82459AD', which is not only able to keep up with up to 225 MHz L2 clock speed, but it can finally cache up to 4 GB of memory. Intel's internal name for the 82459AD is 'tp6e'.
L2 Cache
The third difference between the PII CPUs is the L2 cache that is used. Klamath (PII 233 - 300) used to come with four L2 cache chips rated at 6.5 or 7 ns, thus good enough for L2 cache clocks of 140 MHz (7 ns) or 150 MHz (6.5 ns). The PII 333 is normally using two 5.5 ns L2 cache chips, rated for up to 180 MHz, the 350 and 400 MHz versions come with two 5 ns chips, good for 200 MHz and finally the PII 450 is equipped with 4.4 ns chips, rated for 225 MHz. This difference if of major importance, since the L2 cache is a sensitive part of the Pentium II. Running it way beyond spec will most likely cause L2 cache errors and thus system crashes, even if the CPU core is doing fine at this speed.
Microcode and Intitialization
Finally the last major difference is the microcode update and the CPU initialization that's done each time you boot your system. Different chip revisions have different microcode updates (the code that is loaded into a special CPU-area to fix minor CPU bugs) and, more importantly, different chip revisions have different initialization routines at each different CPU clock. When the system is booting, there are several undocumented CPU 'registers' read by the BIOS, which then sets the L2 cache timings and other things according to the information read from the CPU. This routine cannot be cheated by anyone except the motherboard maker, because nobody knows what information is read and how to react to it.

So far about the basics.

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CPU Type	CPU Speed	Hours/day	Exponent

Estimated Time			Decimal digits