Intel Core i7-3960X vs Intel Core i7-5775R Comparison

The Intel Core i7-3960X and Intel Core i7-5775R represent two very different approaches to desktop computing from Intel, separated by nearly four years of architectural evolution. The 3960X is a 6-core, 12-thread Sandy Bridge-E part designed for maximum multi-threaded throughput, while the 5775R is a 4-core, 8-thread Broadwell chip with a focus on efficiency and integrated graphics. The benchmark data reveals a striking split: the older, larger chip dominates in sustained rendering workloads, while the newer, smaller chip wins decisively in Geekbench tests. Both processors hold the same 45th percentile ranking among all CPUs, with average benchmark scores of 2037 and 2031 respectively, indicating that despite their different strengths, they land in the same overall performance tier.

Head-to-Head Benchmarks

The most immediate observation from the head-to-head data is the near-total victory for the Intel Core i7-3960X across the Cinebench suite. In Cinebench R15 multi-core, the 3960X scores 722 against the 5775R’s 641, a 12.6% advantage. The single-core R15 test shows an even larger gap, with the 3960X posting 102 versus 90, a 13.3% lead. This pattern repeats in Cinebench R20, where the 3960X wins multi-core by 12.7% (3011 vs 2671) and single-core by 13% (425 vs 376). The trend continues into Cinebench R23, with the 3960X ahead by 12.7% in multi-core (7170 vs 6360) and 12.8% in single-core (1012 vs 897).

These numbers tell a clear story: the 3960X is consistently about 12-13% faster in every Cinebench iteration. The consistency across all three versions of the benchmark suggests this is a fundamental performance gap, not a workload-specific anomaly. The 3960X’s two additional cores and four additional threads give it a structural advantage in rendering tasks that Cinebench measures, while its higher 3.90 GHz boost clock (compared to 3.80 GHz on the 5775R) helps in single-threaded portions. The data shows the 3960X winning all six Cinebench tests it appears in.

However, the Geekbench results flip the narrative entirely. In Geekbench multi-core, the 5775R scores 3996 against the 3960X’s 3193, a 20.1% advantage for the newer chip. The single-core Geekbench test is even more lopsided: the 5775R posts 1218 versus 657, a 46.1% margin. This is a massive reversal. The 5775R more than doubles the 3960X’s single-core Geekbench score, and its multi-core score is nearly 25% higher despite having only 4 cores and 8 threads compared to 6 cores and 12 threads.

The interpretation here is that Geekbench measures a different set of capabilities than Cinebench. The 5775R’s Broadwell architecture, built on a 14 nm process versus the 3960X’s 32 nm node, brings substantially improved instructions per clock and newer microarchitectural features. The 5775R also benefits from a dual-channel memory bus with 29.9 GB/s bandwidth, which, while narrower than the 3960X’s quad-channel 51.2 GB/s, is paired with faster memory access patterns in the Broadwell design. The result is a chip that excels in latency-sensitive and branch-heavy workloads typical of Geekbench, while falling behind in sustained multi-threaded rendering where core count and raw throughput matter more.

Where Each One Wins

The Intel Core i7-3960X is the clear winner for multi-core rendering and content creation workloads. Its 12.6-12.7% advantage in Cinebench R15, R20, and R23 multi-core tests shows that tasks like 3D rendering, video encoding, and batch processing will complete noticeably faster on the 3960X. The 6-core, 12-thread configuration provides 50% more physical cores and 50% more threads than the 5775R, which directly translates to higher throughput in parallel workloads. Users running Cinebench-style benchmarks, such as those in Blender or Cinema 4D, will see consistent performance gains with the 3960X.

The 3960X also wins in Cinebench single-core tests, albeit by a smaller margin of 13.3% in R15, 13% in R20, and 12.8% in R23. This is somewhat surprising given the 5775R’s architectural advantage, but the 3960X’s higher boost clock of 3.90 GHz and the specific nature of Cinebench’s single-threaded workload favor the older chip. For tasks that are lightly threaded but rely on the same rendering engine as Cinebench, the 3960X remains competitive.

The Intel Core i7-5775R dominates in Geekbench, which is a more general-purpose benchmark suite that tests a wider range of operations including encryption, compression, memory access patterns, and integer and floating-point performance. The 20.1% multi-core advantage and the staggering 46.1% single-core advantage indicate that the 5775R is far better suited for everyday desktop tasks, office productivity, web browsing, and software development where single-threaded performance and low latency are critical. The 5775R also features integrated Iris Pro Graphics 6200, while the 3960X has no integrated graphics at all, making the 5775R a self-contained solution for light gaming and media playback without a discrete GPU.

For users whose primary workload is Cinebench-style rendering, the 3960X is the obvious choice. For users who run diverse applications, compile code, or use their system for general productivity, the 5775R’s Geekbench dominance suggests it will feel snappier and more responsive in everyday use, despite having fewer cores.

FAQ

Q: Which processor has a higher average benchmark score?

A: The Intel Core i7-3960X has an average benchmark score of 2037, while the Intel Core i7-5775R scores 2031. The difference is negligible, and both sit at the 45th percentile among all CPUs.

Q: How large is the multi-core Cinebench R23 advantage for the 3960X?

A: The 3960X scores 7170 in Cinebench R23 multi-core, compared to the 5775R’s 6360, giving the 3960X a 12.7% lead.

Q: What explains the 5775R’s large Geekbench single-core win?

A: The 5775R scores 1218 in Geekbench single-core versus 657 for the 3960X, a 46.1% margin. This is attributed to the newer Broadwell architecture on a 14 nm process, which provides better instructions per clock than the older Sandy Bridge design on 32 nm.

Q: Do both processors support ECC memory?

A: No, neither the Intel Core i7-3960X nor the Intel Core i7-5775R supports ECC memory, according to the data.

Q: Which processor has a higher boost clock?

A: The Intel Core i7-3960X has a boost clock of 3.90 GHz, while the Intel Core i7-5775R has a boost clock of 3.80 GHz.

Q: How many benchmark wins does each processor have in the head-to-head comparison?

A: The Intel Core i7-3960X wins 6 out of 8 benchmark tests, while the Intel Core i7-5775R wins 2 (both Geekbench tests).

Specification Differences

The two processors differ in nearly every key specification. The Intel Core i7-3960X has 6 cores and 12 threads, while the 5775R has 4 cores and 8 threads. Base clocks are identical at 3.30 GHz, but the boost clocks differ: 3.90 GHz for the 3960X versus 3.80 GHz for the 5775R. The thermal design power is dramatically different, with the 3960X rated at 130 W and the 5775R at 65 W.

The sockets are incompatible: the 3960X uses Intel Socket 2011, while the 5775R uses Intel BGA 1364. The 3960X supports quad-channel DDR3 memory with 51.2 GB/s bandwidth, whereas the 5775R uses dual-channel DDR3 with 29.9 GB/s. PCIe lane counts also differ, with the 3960X providing 40 lanes and the 5775R providing 16 lanes, both Gen 3.

The 3960X has a multiplier that is unlocked, while the 5775R’s multiplier is locked. The 3960X has no integrated graphics, but the 5775R includes Iris Pro Graphics 6200. The 3960X’s launch MSRP was $990, while the 5775R’s launch MSRP was $384. Both are end-of-life products, with the 3960X released on 2011-11-13 and the 5775R on 2015-05-14.

Architecture Differences

The architectural gap between these two CPUs is substantial. The 3960X uses Sandy Bridge architecture (codename Sandy Bridge-E) built on a 32 nm process node, while the 5775R uses Broadwell architecture (codename Broadwell) on a 14 nm process node. The 3960X has 2,270 million transistors on a 435 mm² die, while the 5775R’s transistor count is not specified but its die size is 182 mm².

Both have the same per-core L1 cache (64 KB) and L2 cache (256 KB), but the shared L3 cache differs significantly: the 3960X has 15 MB shared, while the 5775R has 6 MB shared. The 3960X is part of the Core i7 Extreme (Sandy Bridge-E) generation, while the 5775R is from the Core i7 (Broadwell) generation. The 3960X’s memory bus is quad-channel, and the 5775R’s is dual-channel, directly affecting the memory bandwidth figures listed above.

The 5775R’s integrated Iris Pro Graphics 6200 is a major architectural differentiator, as the 3960X relies entirely on a discrete GPU. The 5775R is also a BGA socket part, meaning it is soldered to the motherboard, whereas the 3960X is a socketed LGA 2011 processor. These differences reflect the 3960X’s position as a high-end extreme desktop part aimed at maximum throughput, while the 5775R is a more integrated, power-efficient design.

The Verdict

The data supports a clear split based on workload type. For users running Cinebench or similar multi-threaded rendering tasks, the Intel Core i7-3960X is the better processor. It wins all six Cinebench tests by roughly 12-13%, and its 6-core, 12-thread configuration with 15 MB of L3 cache provides the raw parallel resources needed for such workloads. The 3960X’s quad-channel memory bandwidth of 51.2 GB/s also gives it a data throughput advantage in memory-intensive rendering scenes.

For users who prioritize general system responsiveness, single-threaded performance, or tasks measured by Geekbench, the Intel Core i7-5775R is the clear winner. Its 46.1% single-core and 20.1% multi-core Geekbench advantages are far too large to ignore. The 5775R also runs at 65 W TDP, making it far more power-efficient, and includes integrated graphics, eliminating the need for a separate GPU in basic systems.

The overall average benchmark scores are nearly identical (2037 vs 2031), and both sit at the 45th percentile, so neither is objectively faster across all metrics. The choice comes down to whether the user’s applications resemble Cinebench (choose 3960X) or Geekbench (choose 5775R). The 3960X is a legacy high-end part with a launch MSRP of $990, while the 5775R launched at $384, but both are now end-of-life, so availability and platform compatibility will be practical deciding factors. In short: pick the 3960X for rendering throughput, pick the 5775R for everything else.