Intel Core i7-3960X vs Intel Xeon E3-1585 v5 Comparison

Where Each One Wins

The benchmark data presents an unusual picture: the Intel Core i7-3960X wins every single recorded head-to-head benchmark, yet the two processors are separated by margins so small they are nearly indistinguishable in practice. Across all six Cinebench tests, the largest gap is a mere 1% in Cinebench R15 single-core, where the i7-3960X scores 102 against the Xeon E3-1585 v5's 101. All other deltas hover between 0.3% and 0.5%, making this one of the closest matchups in the database.

The Xeon E3-1585 v5 does not win any of the six recorded benchmark comparisons. However, the database shows it holds a higher overall percentile ranking at 46% versus the i7-3960X's 45%, and its average benchmark score of 2067 edges past the i7's 2037. This suggests the Xeon's advantage lies outside the Cinebench suite, likely in workloads that leverage its integrated graphics or other platform features not captured in the head-to-head data.

The i7-3960X claims victory in every Cinebench iteration, from R15 through R23, in both single-core and multi-core tests. Its multi-core wins are consistent at 0.3% in R15, R20, and R23, while its single-core advantages vary between 0.4% and 1%. The pattern indicates a slight but consistent edge across all rendering workloads, regardless of whether the test emphasizes one thread or all threads.

Architecture Differences

The architectural gap between these two processors spans five years and two process nodes. The Xeon E3-1585 v5 uses Intel's 14 nm Skylake-H design with 2,300 million transistors on a 171 mm² die, while the i7-3960X relies on the 32 nm Sandy Bridge-E architecture with 2,270 million transistors spread across a much larger 435 mm² die. The transistor counts are nearly identical, but the i7 packs them into a die over twice the size, reflecting the older and less dense manufacturing process.

Core counts differ significantly: the Xeon offers 4 cores and 8 threads, while the i7 provides 6 cores and 12 threads. Despite the Xeon's 3.50 GHz base clock versus the i7's 3.30 GHz, both processors boost to 3.90 GHz. The Xeon compensates for fewer cores with higher base frequency, but the i7's additional two cores and four threads give it a structural advantage in multi-threaded workloads.

Cache hierarchies also diverge. The Xeon carries 8 MB of shared L3 cache, while the i7 features 15 MB of shared L3 cache, nearly double. Both maintain identical per-core L1 and L2 allocations at 64 KB and 256 KB respectively. The Xeon's smaller cache reflects its server-oriented design and newer architecture, which typically requires less cache to achieve similar performance.

Memory support reveals fundamental platform differences. The Xeon supports both DDR3 and DDR4 across a dual-channel bus with 34.1 GB/s bandwidth, while the i7 is limited to DDR3 on a quad-channel bus delivering 51.2 GB/s. The i7's wider memory interface provides substantially higher theoretical bandwidth, a critical factor for memory-intensive applications.

The Xeon includes Iris Pro Graphics P580 integrated graphics, ECC memory support, and uses the Intel BGA 1440 socket. The i7 has no integrated graphics, no ECC support, and uses Intel Socket 2011. The i7 offers an unlocked multiplier for overclocking, while the Xeon is locked. PCIe capabilities differ as well: the Xeon provides 16 Gen 3 lanes, while the i7 provides 40 Gen 3 lanes.

Head-to-Head Benchmarks

The closest contest occurs in Cinebench R15 multi-core, where the i7-3960X scores 722 against the Xeon's 720, a 0.3% difference. This near-tie repeats in R20 multi-core (3011 versus 3001) and R23 multi-core (7170 versus 7146), each showing the same 0.3% margin. The consistency across three generations of Cinebench suggests the i7's two additional cores provide a small but reliable advantage, though the Xeon's higher base clock and newer architecture nearly close the gap.

Single-core results follow a similar pattern but with slightly larger spreads. In Cinebench R15 single-core, the i7 leads 102 to 101, a 1% difference. The margin narrows to 0.5% in R20 (425 versus 423) and 0.4% in R23 (1012 versus 1008). The i7's single-core advantage persists despite the Xeon's higher base clock, indicating that the older Sandy Bridge architecture still delivers competitive per-thread performance in these workloads.

The i7 additionally holds Geekbench results in the database, scoring 3193 multi-core and 657 single-core, though no corresponding Xeon Geekbench scores exist for direct comparison. When placed against broader database context, the Xeon's average benchmark score of 2067 places it 0.4% ahead of the AMD Ryzen 5 3400G and 0.4% ahead of the Intel Core i3-10105T, while sitting 0.4% behind the Intel Xeon E5-2628 v3. The i7's average of 2037 places it essentially tied with the AMD Opteron 6386 SE, 0.1% behind the Intel Core i7-7700T, and 0.2% ahead of the AMD Ryzen 5 4500U.

FAQ

Q: Which processor has more cores and threads?

A: The Intel Core i7-3960X has 6 cores and 12 threads, while the Intel Xeon E3-1585 v5 has 4 cores and 8 threads.

Q: Does either processor support ECC memory?

A: Yes, the Intel Xeon E3-1585 v5 supports ECC memory. The Intel Core i7-3960X does not support ECC memory.

Q: Which processor has integrated graphics?

A: The Intel Xeon E3-1585 v5 includes Iris Pro Graphics P580. The Intel Core i7-3960X has no integrated graphics.

Q: What is the difference in L3 cache size?

A: The Intel Xeon E3-1585 v5 has 8 MB of shared L3 cache, while the Intel Core i7-3960X has 15 MB of shared L3 cache.

Q: Which processor wins the most benchmarks?

A: The Intel Core i7-3960X wins all six recorded head-to-head Cinebench benchmarks, with margins ranging from 0.3% to 1%.

Q: Can either processor be overclocked?

A: The Intel Core i7-3960X has an unlocked multiplier for overclocking. The Intel Xeon E3-1585 v5 has a locked multiplier and cannot be overclocked.

The Verdict

The recorded data points to a clear but narrow verdict: the Intel Core i7-3960X outperforms the Intel Xeon E3-1585 v5 in every measured Cinebench test. The margins are small, never exceeding 1%, but they are consistent across all six benchmarks. Users prioritizing raw rendering performance in Cinebench-style workloads should select the i7-3960X.

The Xeon E3-1585 v5 offers distinct platform advantages that the i7 cannot match. Its integrated Iris Pro Graphics P580 provides display output and graphics acceleration without a discrete GPU, a capability entirely absent from the i7. ECC memory support makes it suitable for error-sensitive server or workstation environments where data integrity outweighs raw speed. The Xeon's lower 65 W TDP compared to the i7's 130 W also indicates significantly lower power draw, though the database records no direct power consumption measurements.

The i7-3960X counters with a larger 15 MB L3 cache, quad-channel memory support delivering 51.2 GB/s bandwidth versus the Xeon's 34.1 GB/s, and 40 PCIe Gen 3 lanes versus the Xeon's 16. These features position the i7 for high-bandwidth desktop workloads, multi-GPU configurations, and memory-intensive applications. Its unlocked multiplier also appeals to users seeking overclocking headroom, a feature the locked Xeon cannot offer.

For server and workstation deployments requiring ECC memory, integrated graphics, and lower power consumption, the Xeon E3-1585 v5 is the appropriate choice despite its slight performance deficit. For desktop users prioritizing maximum rendering performance, overclocking capability, and memory bandwidth, the i7-3960X delivers better results in the recorded benchmarks. The performance gap is so small, however, that platform features and system requirements should weigh more heavily than the benchmark differences.

Specification Differences

| Specification | Intel Xeon E3-1585 v5 | Intel Core i7-3960X |

|---|---|---|

| Cores | 4 | 6 |

| Threads | 8 | 12 |

| Base Clock | 3.50 GHz | 3.30 GHz |

| TDP | 65 W | 130 W |

| Socket | Intel BGA 1440 | Intel Socket 2011 |

| Architecture | Skylake | Sandy Bridge |

| Process Node | 14 nm | 32 nm |

| Die Size | 171 mm² | 435 mm² |

| L3 Cache | 8 MB (shared) | 15 MB (shared) |

| Memory Support | DDR3, DDR4 | DDR3 |

| Memory Bus | Dual-channel | Quad-channel |

| Memory Bandwidth | 34.1 GB/s | 51.2 GB/s |

| ECC Memory | Yes | No |

| PCIe Lanes | 16 | 40 |

| Integrated Graphics | Iris Pro Graphics P580 | None |

| Market Segment | Server/Workstation | Desktop |

| Multiplier Unlocked | No | Yes |

| Launch MSRP | $556 | $990 |