Intel Core i5-6400 vs Intel Core i7-3615QM Comparison

The Verdict

The benchmark data presents a sharply split picture. The Intel Core i7-3615QM wins six of eight head-to-head tests, all of them Cinebench workloads, with a consistent advantage of roughly 21.5% over the Intel Core i5-6400. The i5-6400, however, takes both Geekbench tests by a massive margin, leading by 39.2% in multi-core and 47.1% in single-core. This is not a case of one chip being simply better; the two processors are optimized for different measurement methodologies.

For users whose workloads mirror Cinebench, which stresses sustained multi-threaded and single-threaded rendering, the i7-3615QM is the clear pick. Its eight threads allow it to outpace the four-thread i5-6400 in every Cinebench R15, R20, and R23 test. The data shows the i7-3615QM scoring 442 versus 364 in Cinebench R15 multi-core, 1845 versus 1517 in R20 multi-core, and 4393 versus 3614 in R23 multi-core. The single-core Cinebench results follow the same pattern: 62 versus 51 in R15, 260 versus 214 in R20, and 620 versus 510 in R23.

The i5-6400 is the pick for Geekbench-style workloads. Its scores of 3134 multi-core and 1048 single-core dwarf the i7-3615QM's 1907 and 554. The Geekbench suite clearly rewards the newer Skylake architecture's higher base clock of 2.70 GHz versus 2.30 GHz, even though both chips boost to 3.30 GHz. The i5-6400 also holds a higher overall average benchmark score of 1307, compared to 1260 for the i7-3615QM, and edges out its rival in percentile ranking at 35 versus 34.

The verdict depends entirely on the benchmark suite in question. The i7-3615QM is the stronger Cinebench performer, while the i5-6400 dominates Geekbench. The average benchmark scores place them close together, within 3.7% of each other, but the distribution of wins is extreme. The i7-3615QM's nearest rivals include the AMD Athlon 200GE at a 0% delta, while the i5-6400 sits near the AMD Opteron 6328 at 0.2% and the Intel Core i7-3770T at -0.5%, confirming both chips occupy a similar overall performance tier despite their divergent test results.

FAQ

Q: Which processor wins more benchmarks overall?

A: The Intel Core i7-3615QM wins six of the eight head-to-head tests. All six wins are in Cinebench R15, R20, and R23 workloads, both multi-core and single-core variants.

Q: How large is the i7-3615QM's advantage in Cinebench?

A: The edge is consistent and narrow. In Cinebench R15 multi-core, the i7-3615QM leads by 21.4%. In R15 single-core, R20 multi-core, R20 single-core, R23 multi-core, and R23 single-core, the delta is 21.6%, 21.6%, 21.5%, 21.6%, and 21.6% respectively.

Q: Why does the i5-6400 win the Geekbench tests?

A: The i5-6400 scores 3134 in Geekbench multi-core versus 1907 for the i7-3615QM, a 39.2% lead. In single-core, it scores 1048 versus 554, a 47.1% lead. These are the only two tests the i5-6400 wins, but the margins are far larger than the i7-3615QM's Cinebench wins.

Q: Do both processors have the same number of cores?

A: Yes, both have 4 cores. The difference is in threads: the i7-3615QM supports 8 threads, while the i5-6400 supports only 4. The i7-3615QM also has a lower base clock of 2.30 GHz versus 2.70 GHz, though both boost to 3.30 GHz.

Q: Which chip has the higher average benchmark score?

A: The i5-6400 has an average benchmark score of 1307, while the i7-3615QM scores 1260. The i5-6400 also ranks at the 35th percentile versus the 34th percentile for the i7-3615QM.

Q: What is the difference in memory bandwidth?

A: The i5-6400 lists a memory bandwidth of 34.1 GB/s with DDR4 support. The i7-3615QM has no memory bandwidth figure recorded and no memory support type listed, though both use dual-channel memory buses.

Architecture Differences

The two processors come from different architectural generations and target different market segments. The i7-3615QM is a mobile chip based on Ivy Bridge, built on Intel's 22 nm process node with 1,400 million transistors on a 160 mm² die. The i5-6400 is a desktop part based on Skylake, manufactured on the 14 nm node with a larger 177 mm² die size; its transistor count is not recorded.

The core configurations differ in threading. Both have 4 physical cores, but the i7-3615QM adds Hyper-Threading for 8 threads, while the i5-6400 runs 4 threads. The i7-3615QM compensates for its lower 2.30 GHz base clock with the extra threads, while the i5-6400 relies on its higher 2.70 GHz base clock. Both reach 3.30 GHz boost.

Cache hierarchies are identical in structure: 64 KB L1 per core, 256 KB L2 per core, and 6 MB shared L3. The integrated graphics differ, with the i7-3615QM using Intel HD 4000 and the i5-6400 using HD Graphics 530. The i5-6400 supports DDR4 memory with a rated bandwidth of 34.1 GB/s, while the i7-3615QM's memory support is not listed. The i5-6400 also exposes PCIe Gen 3 with 16 lanes from the CPU, a feature not recorded for the i7-3615QM.

The platforms diverge completely. The i7-3615QM uses Intel BGA 1224 and a 45 W TDP, reflecting its mobile design. The i5-6400 uses Intel Socket 1151 and a 65 W TDP, a desktop socket with higher power draw. The i5-6400 is marked end-of-life, while the i7-3615QM has no production status recorded. Both are locked multipliers, and neither supports ECC memory.

Specification Differences

The recorded specifications show clear divergence across every major field except core count and cache. The i7-3615QM has 8 threads versus 4 for the i5-6400. Base clocks differ: 2.30 GHz for the i7-3615QM, 2.70 GHz for the i5-6400. Boost clocks match at 3.30 GHz.

Power and platform differ substantially. The i7-3615QM draws 45 W TDP on Intel BGA 1224, while the i5-6400 draws 65 W TDP on Intel Socket 1151. The i7-3615QM is built on 22 nm with 1,400 million transistors and a 160 mm² die; the i5-6400 uses 14 nm with no transistor count recorded and a 177 mm² die. The i5-6400 lists DDR4 memory support, 34.1 GB/s bandwidth, and PCIe Gen 3 with 16 lanes, none of which are recorded for the i7-3615QM. Integrated graphics are HD 4000 versus HD Graphics 530. The i5-6400 has a launch MSRP of $182, while the i7-3615QM has no MSRP recorded. Release dates show the i7-3615QM arriving on 2012-04-28 and the i5-6400 on 2015-07-01.

Head-to-Head Benchmarks

The Cinebench series is entirely one-sided. In Cinebench R15 multi-core, the i7-3615QM scores 442 against 364 for the i5-6400, a 21.4% win. Single-core R15 shows 62 versus 51, a 21.6% margin. The pattern holds in R20: 1845 versus 1517 multi-core (21.6%) and 260 versus 214 single-core (21.5%). R23 repeats it: 4393 versus 3614 multi-core (21.6%) and 620 versus 510 single-core (21.6%). Every Cinebench test produces a win for the i7-3615QM with a delta between 21.4% and 21.6%.

The Geekbench results flip the script entirely. Geekbench multi-core shows the i5-6400 at 3134 versus 1907 for the i7-3615QM, a 39.2% lead. Single-core is even more lopsided: 1048 versus 554, a 47.1% margin. These are the two largest deltas in the entire comparison, and they belong to the i5-6400.

The overall benchmark averages reflect the split. The i5-6400 averages 1307, the i7-3615QM 1260. The i7-3615QM's nearest rival, the AMD Athlon 200GE, matches it at a 0% delta, while the i5-6400's closest competitor, the AMD Opteron 6328, sits at 0.2%. The i7-3615QM ranks at the 34th percentile of all CPUs; the i5-6400 ranks at the 35th.

Where Each One Wins

The i7-3615QM wins in Cinebench-driven workloads. Its 8 threads provide a clear advantage in multi-threaded rendering, and even its single-core Cinebench scores outperform the i5-6400 despite the lower base clock. Users running Cinebench R15, R20, or R23, or applications with similar threading and instruction patterns, will see a consistent 21.5% performance lead from the i7-3615QM. The 45 W TDP also makes it suitable for mobile platforms, though its socket is limited to BGA 1224.

The i5-6400 wins in Geekbench-style workloads. Its 2.70 GHz base clock, 14 nm Skylake architecture, and DDR4 support with 34.1 GB/s bandwidth contribute to scores of 3134 multi-core and 1048 single-core, which are 39.2% and 47.1% ahead of the i7-3615QM respectively. The i5-6400 also has the higher average benchmark score at 1307, the higher percentile rank at 35, and a desktop socket with PCIe Gen 3 and 16 lanes. For users prioritizing Geekbench results, memory bandwidth, or desktop upgradeability, the i5-6400 is the better fit. Its end-of-life status, however, means it is no longer in production.