CPU Comparison

The Intel Core i7-875K and Intel Core i3-6300 represent two very different eras of desktop computing. The i7-875K is an end-of-life Lynnfield part from the Nehalem generation, built on a 45 nm process with 4 cores and 8 threads. The i3-6300 is an active Skylake part on a 14 nm process with just 2 cores and 4 threads. Despite the i7’s core-count advantage, the benchmark data shows a consistent victory for the newer i3 across every tested workload. The i7-875K’s average benchmark score is 984, while the i3-6300 scores 978, placing them at the 27th and 26th percentiles of all CPUs, respectively. This near-parity in average score masks a significant shift in performance characteristics: the i3-6300 wins all five head-to-head benchmark comparisons, with deltas ranging from -19.1% to -19.5% in favor of the i3.

FAQ

Q: Which processor has more physical cores?

A: The Intel Core i7-875K has 4 physical cores and 8 threads, while the Intel Core i3-6300 has 2 physical cores and 4 threads.

Q: Does the i3-6300 support faster memory than the i7-875K?

A: Yes. The i3-6300 supports DDR4 memory with a dual-channel bus and a memory bandwidth of 34.1 GB/s, whereas the i7-875K supports DDR3 with a dual-channel bus and a memory bandwidth of 21.3 GB/s.

Q: What is the process node difference between the two CPUs?

A: The i7-875K is fabricated on a 45 nm process with 774 million transistors on a 296 mm² die, while the i3-6300 uses a 14 nm process with 1,400 million transistors on a 150 mm² die.

Q: In the head-to-head benchmarks, how many tests does each processor win?

A: The i3-6300 wins all 5 head-to-head benchmark tests. The i7-875K wins 0 tests.

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

A: The largest delta is -19.5% in the Cinebench R20 single-core test, where the i3-6300 scores 200 versus the i7-875K’s 161.

Q: Which processor has integrated graphics?

A: The i3-6300 includes Intel HD 530 integrated graphics. The i7-875K has no integrated graphics listed.

Where Each One Wins

The performance landscape is clear: the i3-6300 dominates every benchmark category. In multi-core tests, the i3-6300 leads by a consistent margin. For example, in Cinebench R15 multi-core, the i3-6300 scores 340 against the i7-875K’s 275, a -19.1% delta. The pattern holds in Cinebench R20 multi-core (1419 vs 1146, -19.2%) and Cinebench R23 multi-core (3380 vs 2729, -19.3%). This is notable because the i7-875K has twice the cores and threads, yet still loses by nearly a fifth in heavily threaded workloads.

Single-core performance shows an even starker gap. The i3-6300 achieves 200 in Cinebench R20 single-core versus 161 for the i7-875K, a -19.5% delta. In Cinebench R23 single-core, the i3-6300 scores 477 against 385, a -19.3% delta. This indicates the Skylake architecture’s IPC advantage is substantial, overcoming the i7’s higher thread count in all scenarios.

The i7-875K has no benchmark wins in this comparison. Its strengths, if any, would have to come from its unlocked multiplier, which allows overclocking, but the data provided shows no scenario where it outperforms the i3-6300. The i3-6300’s wins are not narrow; they are consistent and significant, ranging from 19.1% to 19.5% across all tests.

Architecture Differences

The architectural gap between these two processors is generational. The i7-875K is based on Nehalem architecture with the Lynnfield codename, built on a 45 nm process. It features 774 million transistors on a 296 mm² die. The i3-6300 uses Skylake architecture, also with the Skylake codename, on a 14 nm process. It packs 1,400 million transistors into a much smaller 150 mm² die. This transistor density difference explains why the newer chip can achieve higher performance despite having fewer cores.

Cache hierarchies also differ. Both have 64 KB of L1 cache per core and 256 KB of L2 cache per core. However, the i7-875K has 8 MB of shared L3 cache, while the i3-6300 has only 4 MB. Despite having half the L3 cache, the i3-6300 still wins all benchmarks, indicating that the Skylake memory subsystem and IPC improvements compensate for the reduced cache capacity.

Memory support marks another major architectural split. The i7-875K uses DDR3 memory, while the i3-6300 uses DDR4. The memory bandwidth reflects this: 21.3 GB/s for the i7 versus 34.1 GB/s for the i3. PCIe capabilities also differ, with the i7-875K supporting Gen 2 with 16 lanes (CPU only) and the i3-6300 supporting Gen 3 with 16 lanes (CPU only). The i3-6300 also includes integrated graphics (Intel HD 530), which the i7-875K lacks entirely.

Specification Differences

The specifications reveal why the i3-6300 wins despite fewer cores. The i7-875K has a base clock of 2.93 GHz and a boost clock of 3.60 GHz, with a TDP of 95 watts. The i3-6300 has a higher base clock of 3.80 GHz with no boost clock listed, and a much lower TDP of 51 watts. This clock speed advantage for the i3-6300 is a direct contributor to its single-core dominance.

Socket compatibility is entirely different: the i7-875K uses Intel Socket 1156, while the i3-6300 uses Intel Socket 1151. This means they are not interchangeable in any system. The i7-875K has an unlocked multiplier (true), while the i3-6300’s multiplier is locked (false). This makes the i7-875K more appealing for overclocking, though the data does not include any overclocked benchmark results.

Production status and release dates diverge sharply. The i7-875K was released on 2010-05-29 and is end-of-life, with a launch MSRP of $353. The i3-6300 was released on 2015-08-31 and is still active, with no launch MSRP listed. The process node difference (45 nm vs 14 nm) directly impacts power efficiency, as evidenced by the TDP difference of 95 watts versus 51 watts. Part numbers differ as well: SLBS2 for the i7-875K and SR2HA for the i3-6300.

Head-to-Head Benchmarks

The head-to-head results are remarkably consistent, with the i3-6300 winning every test by roughly the same margin. In Cinebench R15 multi-core, the i3-6300 scores 340 versus 275 for the i7-875K, a delta of -19.1%. This test is particularly telling because it involves multi-threaded rendering, where the i7-875K’s 8 threads should theoretically give it an edge. The i3-6300’s 4 threads still manage to outperform by a wide margin.

Cinebench R20 multi-core shows a similar story: 1419 for the i3-6300 versus 1146 for the i7-875K, a -19.2% delta. The single-core R20 test shows the largest gap at -19.5%, with scores of 200 and 161 respectively. This suggests that the i3-6300’s per-core performance is vastly superior, and that even in multi-core workloads, the i7-875K’s additional threads cannot compensate for slower individual cores.

Cinebench R23 results reinforce the pattern. In multi-core, the i3-6300 scores 3380 versus 2729 for the i7-875K, a -19.3% delta. In single-core, the scores are 477 versus 385, also a -19.3% delta. The consistency of these deltas across different versions of Cinebench indicates a fundamental performance gap rather than a workload-specific anomaly. For context, the i7-875K’s nearest rivals include the Intel Core i3-4130T (avg score 984, 0% delta) and the Intel Xeon X3470 (avg score 983, 0.1% delta). The i3-6300’s nearest rivals include the Intel Core i5-5257U (avg score 976, 0.2% delta) and the Intel Core i3-4130 (avg score 975, 0.3% delta).

The Verdict

The data is unambiguous: the Intel Core i3-6300 is the superior processor in every measured benchmark. Despite having only 2 cores and 4 threads versus the i7-875K’s 4 cores and 8 threads, the i3-6300 wins all five head-to-head tests with deltas between -19.1% and -19.5%. This is a testament to the architectural advancements of Skylake over Nehalem, including the 14 nm process, higher base clock of 3.80 GHz, and support for faster DDR4 memory with 34.1 GB/s bandwidth.

For a user considering these two CPUs, the choice is clear from the performance data alone. The i3-6300 offers better multi-core performance, better single-core performance, lower power consumption (51 watts versus 95 watts), and integrated graphics. It also supports a modern socket (1151) and PCIe Gen 3. The i7-875K’s only advantages are its unlocked multiplier for overclocking and its larger 8 MB L3 cache, but neither translates into a benchmark win in the provided data.

The i7-875K, released in 2010 with a launch MSRP of $353, is end-of-life and represents an older platform. The i3-6300, released in 2015 and still active, is the better choice for any workload represented in the benchmarks. Its 26th percentile ranking versus the i7-875K’s 27th percentile is nearly identical, but the head-to-head results show the i3-6300 is consistently ahead by close to 20%. Anyone choosing between these two should select the i3-6300 based on the benchmark evidence, unless the i7-875K’s overclocking potential on the 1156 socket is a specific requirement. For all standard computing tasks, the i3-6300 is the data-backed winner.