Intel Core i3-1215U vs Intel Core i7-6700K Comparison

The Intel Core i3-1215U and Intel Core i7-6700K represent two very different design philosophies from Intel, separated by nearly seven years of architecture evolution. The i3-1215U is a modern, power-sipping mobile processor built on Alder Lake, while the i7-6700K is a legacy desktop flagship from the Skylake era. Benchmark data reveals a fascinating split: the older desktop chip dominates in most legacy and rendering workloads, while the newer mobile chip counterattacks decisively in math, encryption, and single-threaded PassMark tests. Both processors land in the 67th percentile of all CPUs, yet their performance profiles could not be more distinct.

Head-to-Head Benchmarks

The most striking pattern in the head-to-head data is the i7-6700K’s dominance across the Cinebench suite. In Cinebench R15, R20, and R23, the i7-6700K wins both single-core and multi-core tests by remarkably consistent margins. The multi-core deltas hover around -12.5% for the i3-1215U across all three Cinebench versions, with the i7-6700K scoring 765 vs 669 in R15, 3189 vs 2790 in R20, and 7594 vs 6644 in R23. The single-core Cinebench results tell a similar story, with the i7-6700K leading by 13% in R15 (108 vs 94) and 12.5% in R23 (1072 vs 938). This consistency suggests a fundamental advantage in sustained rendering workloads, likely rooted in the i7-6700K’s higher base clock of 4.00 GHz compared to the i3-1215U’s 1.20 GHz.

Geekbench paints a more nuanced picture. The i7-6700K wins the multi-core test decisively, scoring 5011 against the i3-1215U’s 4365, a -12.9% delta. However, the i3-1215U takes the single-core Geekbench crown with a 3% lead, scoring 1485 versus 1442. This single-core victory is the first hint that the newer architecture has raw per-thread potential, even if the i7-6700K’s higher sustained clocks win in most other single-threaded scenarios.

The PassMark suite delivers the most dramatic swings. The i3-1215U absolutely crushes the i7-6700K in data encryption, scoring 7041 versus 3067 — a staggering 129.6% advantage. Floating-point math also favors the mobile chip heavily, with the i3-1215U scoring 25379 against 17375, a 46.1% lead. Integer math follows suit at 26.3% ahead (35534 vs 28144), and the i3-1215U wins the PassMark multithread test with 10472 points versus 8927, a 17.3% margin. The single-thread PassMark result is another major win for the i3-1215U, which scores 3218 against 2500 — a 28.7% advantage. Even in prime number finding, the i3-1215U edges ahead by 6.7% (32 vs 30).

The i7-6700K fights back in several PassMark categories. It wins data compression by 7.1% (125659 vs 116705), extended instructions by 16.7% (8248 vs 6868), random string sorting by 17.4% (15788 vs 13046), and physics by 8.5% (637 vs 583). Overall, the i7-6700K claims 11 wins to the i3-1215U’s 8, but the magnitude of the i3-1215U’s wins in encryption and floating-point math is far larger than any of the i7-6700K’s margins.

The Verdict

The data points to a clear but conditional recommendation. The Intel Core i7-6700K is the better choice for anyone running Cinebench-style rendering workloads, data compression, string sorting, or physics simulations. Its consistent 12-17% leads in these areas make it the more capable processor for traditional desktop productivity tasks. The i7-6700K also holds the edge in multi-threaded Geekbench performance, suggesting broader real-world application performance in heavily threaded scenarios.

However, the Intel Core i3-1215U is the superior processor for encryption-heavy tasks, floating-point and integer math, and single-threaded PassMark workloads. The 129.6% encryption advantage is not a marginal improvement; it is a generational leap that makes the i3-1215U categorically better for security-related computations. The 46.1% floating-point lead and 28.7% single-thread PassMark win further indicate that modern workloads leveraging newer instruction sets will run significantly faster on the mobile chip.

For a user prioritizing modern security features, mathematical computation, or any workload that benefits from the i3-1215U’s architectural improvements, the choice is clear. For those running legacy software, rendering, or general desktop multitasking, the i7-6700K’s benchmark profile suggests it remains a capable performer despite its age. Both CPUs sit at the same 67th percentile, but they achieve that status through entirely different strengths.

Architecture Differences

The architectural divide between these two processors is substantial. The i3-1215U is built on Intel’s 10 nm process using the Alder Lake architecture, while the i7-6700K uses the 14 nm Skylake design. This process shrink is foundational to many performance differences, enabling the i3-1215U to deliver higher performance per watt and newer instruction set capabilities.

Core configurations differ significantly despite identical thread counts. The i3-1215U features 6 cores and 8 threads, while the i7-6700K has 4 cores and 8 threads. The i3-1215U’s additional physical cores explain its wins in multithreaded PassMark tests, even though the i7-6700K compensates with its much higher 4.00 GHz base clock versus 1.20 GHz. Boost clocks are closer, with the i3-1215U reaching 4.40 GHz and the i7-6700K hitting 4.20 GHz.

Cache hierarchies reveal further divergence. The i3-1215U has 80 KB of L1 cache per core and 1.25 MB of L2 per core, with 10 MB of shared L3. The i7-6700K offers 64 KB L1 per core, 256 KB L2 per core, and 8 MB of shared L3. The i3-1215U’s larger L3 cache and different L2 allocation reflect the Alder Lake design’s emphasis on heterogeneous workloads. The i7-6700K also has a measurable die size of 122 mm², while the i3-1215U’s die size is not listed.

Platform support differs completely. The i3-1215U uses Intel BGA 1744 and supports DDR4 and DDR5 memory in a dual-channel configuration. The i7-6700K uses Intel Socket 1151 and supports DDR3 or DDR4 depending on the motherboard, also dual-channel, but with a listed memory bandwidth of 34.1 GB/s. PCIe capabilities favor the newer chip, with the i3-1215U offering Gen 4 with 20 lanes versus the i7-6700K’s Gen 3 with 16 lanes. Integrated graphics also differ: the i3-1215U has UHD Graphics 64EU, while the i7-6700K has HD Graphics 530.

FAQ

Q: Which processor has more cores?

A: The Intel Core i3-1215U has 6 cores, while the Intel Core i7-6700K has 4 cores. Both have 8 threads.

Q: Is the i3-1215U faster in single-threaded performance?

A: It depends on the benchmark. The i3-1215U wins Geekbench single-core by 3% (1485 vs 1442) and PassMark single-thread by 28.7% (3218 vs 2500), but the i7-6700K wins all Cinebench single-core tests by roughly 12-13%.

Q: What is the biggest performance gap between the two?

A: The largest delta is in PassMark data encryption, where the i3-1215U scores 7041 versus the i7-6700K’s 3067, a 129.6% advantage for the mobile chip.

Q: Which processor supports DDR5 memory?

A: Only the Intel Core i3-1215U supports DDR5, along with DDR4. The Intel Core i7-6700K supports DDR3 or DDR4, depending on the motherboard.

Q: Are both CPUs still in production?

A: No. The i3-1215U is listed as Active, while the i7-6700K is marked as End-of-life.

Q: Which chip has a higher base clock speed?

A: The i7-6700K has a base clock of 4.00 GHz, significantly higher than the i3-1215U’s 1.20 GHz. The i3-1215U’s boost clock of 4.40 GHz is slightly higher than the i7-6700K’s 4.20 GHz.

Where Each One Wins

The Intel Core i7-6700K wins in all Cinebench tests, both single and multi-core, across R15, R20, and R23. This indicates superiority in rendering and content-creation workloads that rely on sustained CPU performance. It also wins PassMark data compression, extended instructions, physics, and random string sorting. These wins suggest the i7-6700K is better suited for tasks like file compression, scientific simulations, and sorting large datasets. Its Geekbench multi-core victory further supports its strength in general-purpose heavy multitasking. The i7-6700K’s higher base clock and desktop-oriented design make it the pick for traditional desktop workloads where power consumption is not a primary concern.

The Intel Core i3-1215U wins in Geekbench single-core and PassMark single-thread, indicating superior per-thread responsiveness in certain modern workloads. Its massive wins in data encryption, floating-point math, integer math, and prime number finding point to strengths in cryptography, numerical analysis, and financial computations. The PassMark multithread win shows that its 6 physical cores can outperform the i7-6700K’s 4 cores in parallel workloads that scale well. The i3-1215U is also the only one of the two with an Active production status, making it the practical choice for new system builds, especially in mobile form factors given its 15W TDP versus the i7-6700K’s 91W TDP.

Specification Differences

| Specification | Intel Core i3-1215U | Intel Core i7-6700K |

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

| Cores | 6 | 4 |

| Base Clock | 1200.00 MHz | 4.00 GHz |

| Boost Clock | 4.40 GHz | 4.20 GHz |

| TDP | 15 W | 91 W |

| Socket | Intel BGA 1744 | Intel Socket 1151 |

| Architecture | Alder Lake | Skylake |

| Codename | Alder Lake-U | Skylake |

| Process Node | 10 nm | 14 nm |

| Die Size | Not listed | 122 mm² |

| L1 Cache | 80 KB (per core) | 64 KB (per core) |

| L2 Cache | 1.25 MB (per core) | 256 KB (per core) |

| L3 Cache | 10 MB (shared) | 8 MB (shared) |

| Memory Support | DDR4, DDR5 | DDR3, DDR4 |

| Memory Bandwidth | Not listed | 34.1 GB/s |

| PCIe | Gen 4, 20 Lanes | Gen 3, 16 Lanes |

| Integrated Graphics | UHD Graphics 64EU | HD Graphics 530 |

| Market Segment | Mobile | Desktop |

| Production Status | Active | End-of-life |

| Release Date | 2022-02-22 | 2015-08-04 |

| Launch MSRP | Not listed | $339 |

| Unlocked Multiplier | No | Yes |

| Part Number | SRLFU | SR2L0SR2BR |