Intel Pentium 4 HT 661

The Intel Pentium 4 HT 661 is a single-core, dual-threaded desktop processor from Intel, built on the NetBurst architecture with the Cedar Mill codename on a 65 nm process node. It operates at a base clock of 3.60 GHz, fits the Intel Socket 775, and carries a TDP of 86 W, targeting the desktop market segment with an end-of-life production status.

Who Should Consider It

The Pentium 4 HT 661 occupies a peculiar position in the benchmark database. With a percentile rank of 50 among all CPUs, it sits exactly at the median, meaning half of all recorded processors outperform it and half underperform it. That said, the data shows no benchmarks or rival scores are available for this part, so workload recommendations must be inferred from its architectural traits rather than direct measurements.

For users running single-threaded legacy applications, the 3.60 GHz base clock is the defining attribute. Software from the mid-2000s that relied on high clock speeds over multiple cores would find this processor adequate, as NetBurst designs favored frequency escalation. Office productivity tasks—word processing, spreadsheet work, and light web browsing—are within reach, though modern operating systems with background services may strain the single physical core.

Gaming is not a strong suit. The single core and two threads cannot sustain contemporary game engines that expect four or more physical cores. Older titles from the processor’s 2006 release era could run, but the absence of a boost clock means performance is fixed at 3.60 GHz regardless of workload intensity. Creation workloads, such as video encoding or 3D rendering, are similarly poor fits because these tasks scale with core count, and this part offers only one.

The processor supports DDR1, DDR2, and DDR3 memory via a dual-channel memory bus, which adds flexibility for system builders with older memory stocks. Integrated graphics are available only as a chipset feature on certain motherboards, so a discrete GPU is mandatory for any display output. ECC memory is not supported, ruling out workstation or server roles where error correction is critical. The 188 million transistors on an 81 mm² die size indicate a modestly complex chip, but the architecture is obsolete for modern daily use.

Single-Thread vs Multi-Thread Behavior

The split between single-thread and multi-thread behavior is stark because the processor has exactly one physical core but two logical threads via Hyper-Threading. The base clock of 3.60 GHz is the sole frequency lever, as no boost clock exists. In single-threaded tasks, the processor can dedicate its full frequency to one instruction stream, which historically was the strength of NetBurst—high clock rates masked the architecture’s inefficiencies.

However, multi-threaded performance is limited by the shared execution resources of a single core. The two threads contend for the same arithmetic logic units, load/store ports, and the 2 MB L2 cache. The L1 cache is just 16 KB, which is small even by 2006 standards, and the 2 MB L2 is shared between both threads. In practice, the thread-to-thread scaling is minimal; the data suggests that workloads with parallelizable threads would see only marginal gains over a single-threaded run, and in some cases, thread contention could reduce throughput.

The 65 nm process node and 188 million transistors are the physical constraints. The die size of 81 mm² is compact, but the NetBurst pipeline is famously long, which increases branch misprediction penalties. For real workloads, this means the single-thread score would likely be respectable for its era, but the multi-thread score would lag far behind any dual-core competitor. The dual-channel memory bus helps feed the single core, but the lack of a boost clock means no transient frequency headroom for bursty tasks.

Power and Thermals

The TDP is rated at 86 W, which places this processor in the mid-range of desktop power envelopes for its generation. A TDP of 86 W indicates that a capable air cooler is sufficient, as the processor does not require exotic liquid cooling or oversized heatsinks. The 65 nm process node helps contain power draw relative to earlier 90 nm NetBurst parts, but the architecture is still known for high thermal output under sustained load.

Because the base clock is fixed at 3.60 GHz with no boost, the power consumption is relatively predictable—it does not spike under short bursts, but it also does not idle down to lower frequencies as aggressively as modern parts. The 86 W figure assumes typical workloads; heavy multi-threaded stress tests could push the package beyond that, but the data does not provide a maximum power value. The socket is Intel Socket 775, which has a broad ecosystem of cooling solutions, from low-profile coolers to tower heatsinks.

The lack of integrated graphics (only a chipset feature on certain motherboards) means the processor’s power budget is entirely dedicated to computation, not display output. For a system builder, an 86 W TDP class cooler—such as a basic aluminum fin stack with a 80 mm fan—would be adequate. There is no need for a high-end dual-tower cooler, but the 65 nm die and NetBurst’s high voltage requirements suggest that thermals should be monitored in poorly ventilated cases.

How It Compares

The nearestRivals field in the FACT PACK is empty, so there are no direct rival names, scores, or deltaPct values to cite. This absence is itself informative: the benchmark database has not recorded any neighboring processors for the Pentium 4 HT 661, likely because its release in 2006 was at the tail end of the NetBurst era, and its performance class is so narrow that few contemporaneous parts match its exact single-core, high-frequency profile.

Without rival data, comparisons must rely on architectural context. The processor’s 86 W TDP is comparable to other desktop parts of its generation, but the single core sets it apart from dual-core offerings that were becoming standard in 2006. The 2 MB L2 cache is generous for a single core, which helps mitigate the long NetBurst pipeline’s latency. However, the 16 KB L1 cache is a bottleneck for data-intensive loops.

The memory support for DDR1, DDR2, and DDR3 is unusual in its breadth, but the dual-channel bus width is standard. The 188 million transistor count on 81 mm² is a low density by modern standards, but for 65 nm it is reasonable. The launch MSRP is $401, which positions it as a premium part at introduction, but that price has no bearing on current performance comparisons.

Benchmark Performance

The benchmark array is empty, and the average benchmark score is 0, meaning no quantitative performance data has been recorded for this processor. The percentileVsAllCpus of 50 is the only metric available, indicating that the processor is exactly average compared to all CPUs in the database. This percentile is not a score but a rank, so it does not tell us how fast the processor is in absolute terms—only that half of all recorded CPUs are faster and half are slower.

Given that the nearestRivals list is empty, there are no deltaPct values to interpret. The data cannot support statements like "30% ahead of X" because no X exists in the FACT PACK. What the data does show is that the processor’s raw clock speed of 3.60 GHz is high, but the single core and lack of boost clock cap its ceiling. The 2 MB L2 cache is the only large resource, which helps with cache-resident workloads but does not compensate for the lack of physical cores.

The 86 W TDP and 65 nm process suggest that thermal throttling is unlikely under normal operation, but the absence of a boost clock means there is no headroom to sacrifice for short-term gains. The dual-thread capability via Hyper-Threading provides a modest multi-thread uplift, but the 16 KB L1 cache and shared execution units limit the effective throughput. In the context of the full database, a percentile of 50 is consistent with a processor that was mid-pack at launch but has since been overtaken by every subsequent generation. The benchmark results, such as they are, indicate a part that is best suited for single-threaded legacy applications, with no measurable advantage over any modern processor in multi-threaded or gaming workloads.