Intel Core i7-3960X vs Intel Core i7-7820HK Comparison

The Intel Core i7-7820HK and the Intel Core i7-3960X represent two very different eras of Intel design, and the benchmark data reflects a sharp split between raw compute workloads and memory-sensitive tasks. The 3960X, a six-core desktop Extreme Edition from 2011, consistently outperforms the newer quad-core mobile chip in Cinebench tests, while the 7820HK turns the tables decisively in Geekbench. The data shows a clear trade-off: the older chip leverages its two additional cores and higher base clock, while the newer chip benefits from architectural improvements that dramatically boost single-threaded and memory performance.

Head-to-Head Benchmarks

The most striking pattern in the head-to-head results is the complete sweep of the Cinebench suite by the Intel Core i7-3960X. Across all six Cinebench tests, the 3960X wins with a remarkably consistent margin. In Cinebench R15 multicore, the 3960X scores 722 against the 7820HK’s 635, a 12% advantage. That margin holds almost exactly in single-core R15, where the 3960X posts 102 versus 89, a 12.7% lead. The pattern repeats in Cinebench R20: the 3960X leads 3011 to 2648 in multicore (12.1%) and 425 to 373 in single-core (12.2%). Cinebench R23 follows suit, with the 3960X ahead 7170 to 6306 in multicore and 1012 to 890 in single-core, both at 12.1% deltas.

The consistency of these deltas is notable. Every Cinebench result lands between 12% and 12.7%, suggesting a stable performance advantage that scales across workload intensities. This is not a case of the older chip winning only in heavily threaded tasks; it wins equally in single-core rendering. The 3960X’s higher base clock of 3.30 GHz versus 2.90 GHz contributes to this, as does its larger 15 MB shared L3 cache compared to the 7820HK’s 8 MB. The boost clocks are identical at 3.90 GHz, so the advantage must come from the core count, cache capacity, and the fact that the 3960X is a desktop part with a 130 W TDP, allowing sustained performance.

The Intel Core i7-7820HK, however, dominates the Geekbench results with margins that dwarf anything the 3960X achieves. In Geekbench multicore, the 7820HK scores 4173 against 3193, a 30.7% win. In single-core, the gap is enormous: 1273 versus 657, a 93.8% lead. This is a massive reversal. The single-core Geekbench result nearly doubles the 3960X’s score, highlighting how far architectural evolution had come by 2017. The 7820HK’s Kaby Lake architecture, built on a 14 nm process, delivers vastly better instructions-per-clock and memory latency characteristics than the 32 nm Sandy Bridge design.

The win count reflects this split: the 3960X takes 6 out of 8 head-to-head benchmarks, while the 7820HK wins 2. However, the magnitude of the 7820HK’s Geekbench wins is far larger than the 3960X’s Cinebench wins. The average benchmark score for the 7820HK is 2048, slightly higher than the 3960X’s 2037, despite the latter winning more individual tests. This suggests that Geekbench’s weighting favors the newer architecture’s strengths, while Cinebench’s rendering workload favors the 3960X’s raw core count and cache.

Where Each One Wins

The Intel Core i7-3960X is the clear winner for rendering and compute-heavy workloads that are well-represented by Cinebench. Its six cores and twelve threads provide a 50% core advantage over the 7820HK’s four cores and eight threads. The data shows this translates into a consistent 12% performance lead across all Cinebench versions, from R15 through R23. This makes the 3960X the better choice for CPU-based rendering tasks, video encoding, and any application that scales with core count and sustained multi-threaded throughput. Its 15 MB L3 cache also helps keep more working data closer to the cores, reducing memory stalls in large datasets.

The Intel Core i7-7820HK wins decisively in Geekbench, which is a more holistic test covering integer, floating-point, and memory performance. The 93.8% single-core advantage is particularly telling. This indicates the 7820HK is far superior for single-threaded applications such as legacy software, many games, and general desktop responsiveness. The 30.7% multicore Geekbench win also suggests that even in multi-threaded scenarios that are not purely compute-bound, the newer architecture’s memory subsystem and instruction set advantages shine. The 7820HK supports both DDR3 and DDR4 memory in dual-channel configuration, while the 3960X is limited to DDR3, albeit in quad-channel.

The practical split is clear: the 3960X for professional rendering and number-crunching, the 7820HK for general-purpose computing, gaming, and any workload that benefits from modern single-thread performance. The 7820HK also has integrated Intel HD Graphics 630, while the 3960X has no integrated graphics, meaning the 7820HK can power a display without a discrete GPU, a distinct usability advantage for mobile systems.

FAQ

Q: Which processor has a higher average benchmark score?

A: The Intel Core i7-7820HK has an average benchmark score of 2048, while the Intel Core i7-3960X scores 2037, a difference of 11 points in favor of the 7820HK.

Q: How do the two chips compare in Cinebench R23 multicore?

A: The Intel Core i7-3960X scores 7170, which is 12.1% higher than the 7820HK’s 6306 in the same test.

Q: What is the largest performance gap in the head-to-head results?

A: The largest gap is in Geekbench single-core, where the Intel Core i7-7820HK scores 1273, a 93.8% improvement over the 3960X’s 657.

Q: Do both processors have unlocked multipliers?

A: Yes, both the Intel Core i7-7820HK and the Intel Core i7-3960X have multiplierUnlocked set to true, indicating they are overclockable.

Q: What is the memory bandwidth difference between the two?

A: The Intel Core i7-3960X has a specified memory bandwidth of 51.2 GB/s with quad-channel DDR3 support. The 7820HK has no memory bandwidth figure listed, but it supports dual-channel DDR3 or DDR4.

Q: Which processor has a larger L3 cache?

A: The Intel Core i7-3960X has 15 MB of shared L3 cache, compared to the 7820HK’s 8 MB of shared L3 cache.

Specification Differences

The two processors differ in nearly every fundamental specification. The Intel Core i7-7820HK has 4 cores and 8 threads, while the 3960X has 6 cores and 12 threads. Base clocks differ substantially: the 7820HK runs at 2.90 GHz, the 3960X at 3.30 GHz, though both boost to 3.90 GHz. The TDP difference is stark: 45 W for the 7820HK versus 130 W for the 3960X. Sockets are entirely different, with the 7820HK using Intel BGA 1440 and the 3960X using Intel Socket 2011.

Memory support diverges: the 7820HK supports both DDR3 and DDR4 in dual-channel mode, while the 3960X supports only DDR3 but in quad-channel mode, yielding a listed memory bandwidth of 51.2 GB/s. The 7820HK has 16 PCIe Gen 3 lanes, while the 3960X has 40 PCIe Gen 3 lanes. The 7820HK includes integrated Intel HD Graphics 630; the 3960X has no integrated graphics. The 3960X has 2,270 million transistors and a die size of 435 mm², while the 7820HK has no transistor count listed but a die size of 126 mm².

Architecture Differences

The architectural gap between the two is generational. The 7820HK is built on Kaby Lake architecture with a 14 nm process node, while the 3960X uses Sandy Bridge on a 32 nm node. The 7820HK belongs to the Kaby Lake-H codename family and the Core i7 (Kaby Lake-H) generation. The 3960X is from the Sandy Bridge-E codename family and the Core i7 Extreme (Sandy Bridge-E) generation. This 14 nm versus 32 nm difference explains the massive transistor density and power efficiency gap: the 7820HK fits 126 mm² of silicon into a 45 W envelope, while the 3960X requires 435 mm² and 130 W.

L1 and L2 caches are identical per core at 64 KB and 256 KB respectively, but L3 cache differs significantly: 8 MB shared on the 7820HK versus 15 MB shared on the 3960X. The 3960X also lists a transistor count of 2,270 million, while the 7820HK does not specify one. Integrated graphics are present on the 7820HK as Intel HD Graphics 630, absent on the 3960X. Release dates are far apart: the 7820HK launched in 2017, the 3960X in 2011. Both are end-of-life production status.

The 7820HK’s 14 nm process allows higher clock speeds at far lower power, but the 3960X compensates with more cores and a larger cache. The 3960X’s quad-channel memory bus provides higher theoretical bandwidth, but the 7820HK’s newer memory controller likely offers lower latency. The 7820HK supports DDR4, which the 3960X cannot, giving it a modern memory standard advantage.

The Verdict

The data supports a straightforward conclusion: the Intel Core i7-3960X is the better choice for sustained multi-threaded rendering workloads, as evidenced by its consistent 12% lead across all Cinebench versions. Its six cores, 12 threads, and 15 MB L3 cache deliver tangible benefits in CPU-bound rendering tasks. The 7820HK cannot match this in Cinebench, despite its architectural advantages.

However, the Intel Core i7-7820HK is the superior processor for general-purpose computing and single-threaded performance. Its 93.8% Geekbench single-core lead and 30.7% Geekbench multicore lead are enormous, indicating far better real-world responsiveness, gaming performance, and efficiency in modern software. The 7820HK also offers integrated graphics, DDR4 support, and a fraction of the TDP at 45 W versus 130 W, making it viable for thin-and-light laptops.

The percentile rankings are nearly identical, with the 7820HK at the 46th percentile and the 3960X at the 45th percentile of all CPUs. The average benchmark scores are also close, 2048 versus 2037. This means that for a typical mixed workload, the two chips will perform similarly overall. The decision hinges on workload type: choose the 3960X for pure compute and rendering, choose the 7820HK for everything else, especially if power efficiency, integrated graphics, or modern memory support are priorities.