Pentium 4 HT 651 vs Pentium D 840
Primary details
Comparing Pentium D 840 and Pentium 4 HT 651 processor market type (desktop or notebook), architecture, sales start time and price.
| Place in the ranking | not rated | not rated |
| Place by popularity | not in top-100 | not in top-100 |
| Market segment | Desktop processor | Desktop processor |
| Architecture codename | Smithfield (2005) | Cedar Mill (2006) |
| Release date | May 2005 (19 years ago) | January 2006 (18 years ago) |
Detailed specifications
Pentium D 840 and Pentium 4 HT 651 basic parameters such as number of cores, number of threads, base frequency and turbo boost clock, lithography, cache size and multiplier lock state. These parameters indirectly say of CPU speed, though for more precise assessment you have to consider their test results.
| Physical cores | 2 (Dual-core) | 1 (Single-Core) |
| Threads | 2 | 2 |
| Base clock speed | 3.2 GHz | no data |
| Boost clock speed | 3.2 GHz | 3.4 GHz |
| L1 cache | 28 KB | 28 KB |
| L2 cache | 2 MB | 2 MB |
| L3 cache | 0 KB | 0 KB |
| Chip lithography | 90 nm | 65 nm |
| Die size | 206 mm2 | 81 mm2 |
| Maximum core temperature | 70 °C | no data |
| Number of transistors | 169 million | 188 million |
| 64 bit support | + | + |
| Windows 11 compatibility | - | - |
| VID voltage range | 1.2V-1.4V | no data |
Compatibility
Information on Pentium D 840 and Pentium 4 HT 651 compatibility with other computer components: motherboard (look for socket type), power supply unit (look for power consumption) etc. Useful when planning a future computer configuration or upgrading an existing one. Note that power consumption of some processors can well exceed their nominal TDP, even without overclocking. Some can even double their declared thermals given that the motherboard allows to tune the CPU power parameters.
| Number of CPUs in a configuration | 2 | 1 |
| Socket | PLGA775 | 775 |
| Power consumption (TDP) | 130 Watt | 86 Watt |
Technologies and extensions
Technological solutions and additional instructions supported by Pentium D 840 and Pentium 4 HT 651. You'll probably need this information if you require some particular technology.
| Enhanced SpeedStep (EIST) | + | no data |
| Turbo Boost Technology | - | no data |
| Hyper-Threading Technology | - | no data |
| Idle States | + | no data |
| Demand Based Switching | - | no data |
| PAE | 32 Bit | no data |
| FSB parity | - | no data |
Security technologies
Pentium D 840 and Pentium 4 HT 651 technologies aimed at improving security, for example, by protecting against hacks.
| TXT | - | no data |
| EDB | + | no data |
Virtualization technologies
Virtual machine speed-up technologies supported by Pentium D 840 and Pentium 4 HT 651 are enumerated here.
| VT-d | - | no data |
| VT-x | - | no data |
Memory specs
Types, maximum amount and channel quantity of RAM supported by Pentium D 840 and Pentium 4 HT 651. Depending on the motherboard, higher memory frequencies may be supported.
| Supported memory types | DDR1, DDR2, DDR3 | DDR1, DDR2, DDR3 |
Pros & cons summary
| Physical cores | 2 | 1 |
| Chip lithography | 90 nm | 65 nm |
| Power consumption (TDP) | 130 Watt | 86 Watt |
Pentium D 840 has 100% more physical cores.
Pentium 4 HT 651, on the other hand, has a 38.5% more advanced lithography process, and 51.2% lower power consumption.
We couldn't decide between Pentium D 840 and Pentium 4 HT 651. We've got no test results to judge.
Should you still have questions on choice between Pentium D 840 and Pentium 4 HT 651, ask them in Comments section, and we shall answer.
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