Intel Core i7-3840QM

The Intel Core i7-3840QM is a mobile quad-core processor built on the Ivy Bridge architecture, released in September 2012. It operates with a base clock of 2.80 GHz and a boost clock of 3.80 GHz, with 4 cores and 8 threads via Hyper-Threading. The chip is fabricated on Intel's 22 nm process, containing 1,400 million transistors on a 160 mm² die. It features 64 KB of L1 cache per core, 256 KB of L2 per core, and 8 MB of shared L3 cache. Memory support is limited to dual-channel DDR3, and it integrates an Intel HD 4000 GPU. With a TDP of 45 W, it is designed for laptops and uses the Intel BGA 1224 socket. In the benchmark database, the i7-3840QM achieves an average benchmark score of 1431, placing it in the 38th percentile of all CPUs — a position that reflects its age and mobile orientation.

Benchmark Performance

The i7-3840QM's benchmark results show a clear split between single-threaded and multi-threaded performance. In Cinebench R23, it scores 5020 in the multicore test and 708 in the single-core test. The R20 run yields 2108 multicore and 297 single-core, while R15 gives 505 multicore and 71 single-core. Geekbench reports 2111 multicore and 628 single-core. These numbers, taken together, indicate a processor that scales well with thread count but trails modern parts in per-core throughput.

Relative to its nearest rivals, the i7-3840QM is essentially tied. The closest competitor, the Intel Core i5-4570S, has an average score of 1429, just 0.2% behind the i7-3840QM's 1431. The Intel Core i7-2700K averages 1424, a 0.5% gap. The Intel Xeon Bronze 3106 scores 1423, 0.6% lower, and the Intel Core i7-3820 also scores 1422, a 0.6% deficit. All four rivals fall within a margin of 0.6% of the i7-3840QM, meaning the mobile chip delivers performance statistically indistinguishable from these desktop and server parts in the aggregate benchmark suite.

The multi-thread scores are particularly telling. In Cinebench R23, the multicore result of 5020 is more than seven times the single-core score of 708. That scaling factor indicates efficient use of the 4-core/8-thread configuration under heavy parallel load. The R20 and R15 ratios are similar, at roughly 7.1x and 7.1x, respectively. Geekbench, however, shows a much lower multi-to-single ratio of about 3.36x, suggesting that the Geekbench workload does not scale as well across the eight threads, possibly due to memory bandwidth limitations or the nature of the test. This discrepancy is worth noting for users who rely on Geekbench as a primary reference.

How It Compares

Intel Core i5-4570S — The i5-4570S averages 1429, a 0.2% deficit relative to the i7-3840QM. This desktop part, despite being a lower-tier i5, matches the mobile i7 almost exactly in aggregate performance. The i7-3840QM's advantage is minimal, but it does hold the edge in the averaged benchmark suite.

Intel Core i7-2700K — The i7-2700K, a desktop Sandy Bridge chip, scores 1424 on average, 0.5% behind the i7-3840QM. The i7-3840QM's Ivy Bridge architecture and higher boost clock likely compensate for the older design's higher base clock and unlocked multiplier (which is not present on the mobile chip). The performance gap is negligible in practice.

Intel Xeon Bronze 3106 — The Xeon Bronze 3106, a server processor, averages 1423, 0.6% lower. Despite being a newer platform with more cores (though the FACT PACK does not list its core count), the Xeon's aggregate score is effectively identical to the i7-3840QM. This suggests that the i7-3840QM's single-thread performance and clock speed help it compete against a lower-clocked server part.

Intel Core i7-3820 — The i7-3820, a desktop Sandy Bridge-E chip, scores 1422, also 0.6% behind. This comparison is particularly interesting because the i7-3820 is a quad-core with similar specifications, yet the i7-3840QM edges it out in the average. The mobile chip's higher boost clock (3.80 GHz vs the i7-3820's unspecified boost) may contribute, but the data shows a near-tie.

Who Should Consider It

The i7-3840QM is best suited for users running legacy software that can utilize multiple threads. Its Cinebench R23 multicore score of 5020 indicates it can handle rendering, video encoding, and other parallel workloads from its era, though modern applications will likely demand more. For single-threaded tasks, the R23 single-core score of 708 is modest; office productivity, web browsing, and light coding will run adequately, but the processor will not excel in heavily single-threaded modern titles.

Gaming performance, while not directly benchmarked, can be inferred from the single-core scores. The 3.80 GHz boost clock helps, but the integrated HD 4000 GPU is not designed for demanding 3D workloads. Users planning to play older games or use the chip for general productivity will find it sufficient, but those expecting high frame rates in current titles should look elsewhere. The 45 W TDP makes it suitable for laptops where power efficiency is a priority, and the dual-channel DDR3 memory support is adequate for the era.

Content creators working with software that scales across cores — such as video editors or 3D renderers — will benefit from the 4-core/8-thread design. The R20 multicore score of 2108 and R15 multicore of 505 confirm that the processor can handle moderate parallel workloads. However, given its 38th percentile standing, it is below the median of all CPUs in the database, so users with demanding modern workloads will likely find it insufficient.

Platform and Compatibility

The i7-3840QM uses the Intel BGA 1224 socket, which is a soldered, non-upgradeable package. This means the processor is permanently attached to the motherboard, eliminating any possibility of a future CPU upgrade. It supports dual-channel DDR3 memory, with no ECC capability. The integrated graphics are provided by the Intel HD 4000, which is suitable for basic display output and video playback.

The chip is built on Intel's 22 nm process, with a die size of 160 mm² and 1,400 million transistors. It supports a maximum of 8 MB of shared L3 cache. The memory controller is limited to DDR3, and there is no information about PCIe lanes in the FACT PACK; users should consult motherboard documentation for expansion options. The release date is September 2012, placing it in the Ivy Bridge generation. The multiplier is locked, so overclocking is not possible. The part number is SR0UU.

FAQ

Q: What is the boost clock speed of the Intel Core i7-3840QM?

A: The boost clock is 3.80 GHz, while the base clock is 2.80 GHz.

Q: Does the i7-3840QM support ECC memory?

A: No, ECC memory is not supported. The chip uses dual-channel DDR3 memory.

Q: How much L3 cache does the i7-3840QM have?

A: It has 8 MB of shared L3 cache, along with 64 KB L1 and 256 KB L2 per core.

Q: Is the multiplier unlocked for overclocking?

A: No, the multiplier is locked, so the processor cannot be overclocked.

Q: What integrated graphics does the i7-3840QM include?

A: It integrates the Intel HD 4000 GPU.

Q: What is the TDP of this processor?

A: The TDP is 45 W, making it suitable for mobile platforms.

Single-Thread vs Multi-Thread Behavior

The i7-3840QM exhibits a pronounced difference between single-thread and multi-thread performance. In Cinebench R23, the single-core score of 708 is modest, but the multicore score of 5020 shows that the processor can effectively leverage all eight threads. The ratio of about 7.1x indicates near-linear scaling for this workload, which is typical for rendering tasks that distribute well across cores. The R20 and R15 results follow the same pattern, with multicore scores of 2108 and 505 against single-core scores of 297 and 71, respectively.

Geekbench tells a different story. The single-core score of 628 and multicore score of 2111 produce a ratio of only about 3.36x. This suggests that the Geekbench benchmark does not scale as well with thread count, possibly because the test includes memory-bound or latency-sensitive components that limit parallel efficiency. For users who rely on Geekbench, the i7-3840QM will appear less impressive in multi-threaded tasks than Cinebench would indicate.

In real-world terms, this means the processor will excel in applications that are explicitly designed to use many threads, such as video encoding or 3D rendering, where the multicore scores are strong. For single-threaded tasks — like spreadsheet calculations, web browsing, or older games — the performance is adequate but not exceptional. The 3.80 GHz boost clock helps mitigate the low per-core IPC, but the chip's age is evident in the single-core numbers. Overall, the i7-3840QM is a balanced mobile processor for its time, with multi-threaded capability that punches above its single-thread standing.