AMD Phenom II X4 805

The AMD Phenom II X4 805 is a 4-core, 4-thread desktop processor built on the 45 nm K10 “Deneb” architecture, released in early 2009 and now end-of-life. It operates at a fixed 2.50 GHz base clock with no boost, drawing a 95 W TDP and fitting the AMD Socket AM3 platform. Its benchmark profile places it in the lower tier of modern processors, with an average score of 585 and a percentile rank of 12 among all CPUs, meaning it outperforms only a small fraction of the database's tracked processors.

Benchmark Performance

The Phenom II X4 805’s raw scores are modest by contemporary standards, but they reveal a consistent pattern across rendering workloads. In Cinebench R15 multi-core, it scores 171 points; in R20 multi-core, it reaches 714 points; and in R23 multi-core, it hits 1700 points. These are sequential versions of the same workload, so the scaling from R15 to R23 is expected, but the absolute values confirm a processor that is far from competitive with modern desktop chips. Single-thread performance is even more limited: the R20 single-core score is 100 points, and the R23 single-core score is 240 points. These numbers indicate a CPU that was designed for an era when multi-threaded applications were less common, and they highlight the architectural age of the K10 core.

The average benchmark score of 585 places the Phenom II X4 805 in a tight cluster with its nearest rivals. Against the AMD Athlon II X4 615e, the delta is exactly 0%, meaning the two processors are statistically identical in aggregate performance. The AMD Athlon II X3 460 and Intel Core M-5Y71 each score 583, putting the Phenom II X4 805 a marginal 0.4% ahead of both. The AMD A10-5757M scores 588, which is 0.5% higher than the Phenom II X4 805. These deltas are all within noise levels, so the practical takeaway is that the Phenom II X4 805 performs at the same level as these four rivals, none of which are modern high-end parts. The 12th percentile ranking reinforces this: 88% of all CPUs in the database perform better.

How It Compares

AMD Athlon II X4 615e: This rival matches the Phenom II X4 805 exactly, with both scoring 585 on average. The 0% delta means there is no measurable performance difference between the two in aggregate benchmarks. The Athlon II X4 615e is a lower-power variant in the same family, so users choosing between them would be deciding on power characteristics rather than speed.

AMD Athlon II X3 460: The Phenom II X4 805 leads this triple-core chip by 0.4%, a negligible margin given the score difference of 585 versus 583. The extra core on the Phenom II X4 805 provides a slight edge, but the Athlon II X3 460 is close enough that real-world differences would be imperceptible in most tasks.

Intel Core M-5Y71: This low-power mobile chip also scores 583, trailing the Phenom II X4 805 by 0.4%. The comparison is interesting because the Core M-5Y71 is a much newer, energy-efficient design, yet it lands in the same performance tier. This suggests the Phenom II X4 805’s four full cores still hold their own against a dual-core with hyper-threading from a later generation.

AMD A10-5757M: The A10-5757M scores 588, which is 0.5% higher than the Phenom II X4 805. This is the only rival that edges ahead, but the margin is so small that it falls within typical benchmark variance. The A10-5757M is an accelerated processing unit with integrated graphics, so its slight lead in CPU benchmarks does not necessarily translate to a better overall experience.

Power and Thermals

The Phenom II X4 805 carries a 95 W TDP, which is a standard figure for a quad-core desktop processor from its generation. This TDP class implies the need for a capable air cooler, but it does not demand anything exotic like liquid cooling or a high-end tower heatsink. A stock AMD cooler from that era would be sufficient for stock operation, given the 45 nm process node and the relatively low 2.50 GHz clock speed. The 95 W rating also means that system builders should ensure adequate case airflow, but the thermal load is manageable by modern standards. The lack of a boost clock means the processor runs at a constant frequency under load, which simplifies thermal behavior — there is no burst of higher heat output from turbo frequencies. For a modern user repurposing this chip, a basic aftermarket air cooler would provide a comfortable margin, but the stock solution is adequate at the factory TDP.

FAQ

Q: What is the average benchmark score of the AMD Phenom II X4 805?

A: The average benchmark score is 585, which places it in the 12th percentile of all CPUs tracked in the database.

Q: How does the Phenom II X4 805 compare to the AMD Athlon II X4 615e?

A: The two processors have identical average scores of 585, resulting in a 0% performance delta. They are effectively tied in aggregate benchmarks.

Q: Does the Phenom II X4 805 support ECC memory?

A: Yes, ECC memory is supported, which is a feature that can be relevant for basic workstations or servers using this platform.

Q: What is the memory bandwidth of the Phenom II X4 805?

A: The dual-channel DDR3 memory interface provides a memory bandwidth of 21.3 GB/s.

Q: Is the multiplier unlocked on the Phenom II X4 805?

A: No, the multiplier is locked, meaning overclocking is limited to adjusting the base clock or other platform settings, not the multiplier itself.

Q: What is the process node for this processor?

A: The Phenom II X4 805 is built on a 45 nm process, which is a key factor in its 95 W TDP and older power characteristics.

Platform and Compatibility

The Phenom II X4 805 uses the AMD Socket AM3, which provides compatibility with a range of motherboards from the late 2000s and early 2010s. It supports DDR3 memory in a dual-channel configuration, with a memory bandwidth of 21.3 GB/s, and it includes ECC memory support, which is uncommon for consumer desktop chips. PCIe Gen 2 is the available interface, which is adequate for graphics cards and storage from that era but will bottleneck modern high-end GPUs. Integrated graphics are not on the processor itself; the fact pack notes that graphics are available "on certain motherboards (Chipset feature)," meaning any display output depends on the motherboard's chipset rather than the CPU. The upgrade path is limited by the AM3 socket: users can move to other AM3 Phenom II or Athlon II processors, but there is no forward compatibility with newer sockets like AM3+ or AM4. The part number is HDX805WFK4FGI, and the processor is end-of-life, so new units are not available, and used options should be evaluated carefully. The 758 million transistors on a 258 mm² die reflect the mature 45 nm design, and the 4 MB shared L3 cache is a defining feature of the Deneb architecture.

Single-Thread vs Multi-Thread Behavior

The benchmark data shows a stark contrast between single-thread and multi-thread performance. In Cinebench R20, the multi-core score is 714, while the single-core score is 100 — a 7.14x ratio, which is far higher than the 4-core/4-thread configuration would suggest. This indicates that the multi-core score benefits from parallel scaling across all four cores, but the single-core score is extremely low, reflecting the 2.50 GHz clock speed and the older K10 architecture's limited instructions-per-clock. In Cinebench R23, the multi-core score is 1700 and the single-core score is 240, a 7.08x ratio, which is consistent with the R20 results. For real workloads, this split means the Phenom II X4 805 is acceptable for multi-threaded tasks like video encoding or rendering, where all four cores are utilized, but it will struggle with single-threaded applications such as older games or lightly threaded productivity software. The single-core scores of 100 (R20) and 240 (R23) are among the lowest in the database, so any workload that depends on a single thread will feel sluggish. Conversely, the multi-core scores, while still low in absolute terms, show that the processor can scale reasonably well when the workload is parallelized. Users should prioritize multi-threaded applications for this CPU, as its single-thread performance is a clear bottleneck.