Intel Core i7-2600K vs Intel Core i7-3720QM Comparison

The Intel Core i7-2600K and Intel Core i7-3720QM represent two very different philosophies from the same manufacturer: the former is a desktop enthusiast part, the latter a mobile efficiency chip. Both are quad-core, eight-thread processors from the Core i7 family, but their benchmark results and physical characteristics tell a story of divergent priorities. The data shows a near-split in performance wins, with the mobile chip taking five of eight head-to-head tests, while the desktop chip claims three, including the most decisive victories.

Head-to-Head Benchmarks

The most striking result is in Geekbench, where the i7-2600K outperforms the i7-3720QM by a significant margin. In Geekbench multicore, the 2600K scores 2613 against the 3720QM’s 2457, a delta of 6.3%. The single-core gap is nearly as large: 768 versus 726, a 5.8% advantage. This is the 2600K’s territory—its higher base and boost clocks, 3.40 GHz and 3.80 GHz respectively, give it a clear edge in workloads that are sensitive to raw frequency.

However, the Cinebench suite tells a different story. Across all six Cinebench tests (R15, R20, and R23, each with multicore and single-core variants), the i7-3720QM either wins or ties. The multicore results are consistent: the 3720QM scores 475, 1981, and 4718 in R15, R20, and R23 respectively, while the 2600K scores 469, 1955, and 4657. Each of these represents a 1.3% advantage for the mobile chip. The single-core Cinebench results are similarly close: the 3720QM leads R20 single-core 279 to 275 (1.4% delta) and R23 single-core 666 to 657 (1.4% delta), while R15 single-core is a dead tie at 66 points each.

What does this mean? The data indicates that the i7-3720QM, despite running at lower clock speeds, is slightly more efficient in per-cycle execution in Cinebench’s rendering workloads. Its 22 nm Ivy Bridge architecture delivers more instructions per clock than the 32 nm Sandy Bridge design of the 2600K. The average benchmark score across all tests reinforces this: the 2600K averages 1433, while the 3720QM averages 1421, a difference of less than 1%. Both CPUs sit at the 37th percentile of all CPUs, placing them in the same general performance tier.

Architecture Differences

The architectural gap between these two chips is a full generation. The i7-2600K uses Sandy Bridge, built on Intel’s 32 nm process, while the i7-3720QM uses Ivy Bridge, built on a 22 nm process. This process shrink is fundamental: the 3720QM packs 1,400 million transistors onto a 160 mm² die, whereas the 2600K has 1,160 million transistors on a larger 216 mm² die. The denser, newer process is a major reason why the mobile chip can match or exceed desktop performance at a much lower TDP.

Cache configuration also differs. Both chips have 64 KB of L1 and 256 KB of L2 per core, but the shared L3 cache is where they diverge: the 2600K has 8 MB of shared L3, while the 3720QM has only 6 MB. This 2 MB deficit in the mobile part is notable, yet it does not appear to hurt its performance in the benchmark results. The integrated graphics are also different: the 2600K pairs with Intel HD 3000, while the 3720QM features Intel HD 4000. Memory support is identical in terms of bus width (dual-channel DDR3), and the 2600K has a documented memory bandwidth of 25.6 GB/s, while the 3720QM’s bandwidth is not listed in the data.

The most critical physical difference is TDP and socket. The 2600K has a 95 W TDP and uses Intel Socket 1155, while the 3720QM has a 45 W TDP and uses Intel BGA 1224, a soldered mobile package. The 2600K has an unlocked multiplier, making it a classic overclocking part, whereas the 3720QM’s multiplier is locked. The 2600K also lists PCIe Gen 2 with 16 lanes (CPU only), while the 3720QM’s PCIe configuration is not provided.

FAQ

Q: Which processor is faster in Cinebench R23 multicore?

A: The Intel Core i7-3720QM scores 4718, which is 1.3% higher than the 2600K’s 4657.

Q: Does the i7-2600K win any benchmark tests?

A: Yes, it wins both Geekbench tests. It scores 2613 in multicore and 768 in single-core, beating the 3720QM by 6.3% and 5.8% respectively.

Q: How do the average benchmark scores compare?

A: The 2600K has an average score of 1433, while the 3720QM averages 1421. This is a 0.8% difference in favor of the desktop chip.

Q: Are they in the same performance percentile?

A: Yes, both are in the 37th percentile of all CPUs, indicating they perform at essentially the same level overall.

Q: What is the TDP difference between the two?

A: The 2600K has a TDP of 95 W, while the 3720QM has a TDP of 45 W, making the mobile chip significantly more power-efficient.

Q: Can the i7-3720QM be overclocked?

A: No, its multiplier is locked. The i7-2600K, by contrast, has an unlocked multiplier.

Specification Differences

The two chips differ in nearly every physical and feature specification. The 2600K has a base clock of 3.40 GHz and a boost clock of 3.80 GHz, while the 3720QM runs at 2.60 GHz base and 3.60 GHz boost. The 2600K has a 95 W TDP versus the 3720QM’s 45 W. The socket is completely different: Intel Socket 1155 for the desktop chip, Intel BGA 1224 for the mobile chip. The process node is 32 nm for the 2600K and 22 nm for the 3720QM. Transistor count is 1,160 million versus 1,400 million, and die size is 216 mm² versus 160 mm². L3 cache is 8 MB on the 2600K versus 6 MB on the 3720QM. The integrated graphics are Intel HD 3000 versus Intel HD 4000. The 2600K is a desktop part with an unlocked multiplier, while the 3720QM is a mobile part with a locked multiplier. The 2600K has a launch MSRP of $317; the 3720QM has no listed launch MSRP. The 2600K uses PCIe Gen 2 with 16 lanes (CPU only), while the 3720QM’s PCIe specs are not listed. Memory bandwidth is 25.6 GB/s for the 2600K, while the 3720QM’s is not listed. Finally, the 2600K is marked as end-of-life, while the 3720QM’s production status is not given.

The Verdict

The benchmark data presents a fascinating case of a mobile chip matching a desktop chip from the previous generation. The i7-3720QM wins five of eight tests, but its victories are narrow—all between 1.3% and 1.4%. The i7-2600K wins three tests, but its Geekbench victories are decisive, at 5.8% and 6.3%. The average scores are within 1% of each other, and both sit at the 37th percentile. This means that for most general-purpose computing, the two are effectively interchangeable in performance.

The choice between them should be dictated by platform, not raw speed. The 2600K is a desktop processor with an unlocked multiplier, designed for users who want to overclock and push performance beyond stock. Its higher TDP of 95 W and larger die size suggest it was built for sustained, high-power operation in a desktop chassis. The 3720QM is a mobile chip with a locked multiplier and a 45 W TDP, engineered for laptops where power draw and heat dissipation are critical. Its soldered BGA 1224 socket means it is not a user-upgradeable part.

If you are building or upgrading a desktop system with an LGA 1155 motherboard, the 2600K is the clear choice—it offers the same average performance as the 3720QM but with overclocking headroom. If you are looking at a laptop, the 3720QM is the only option of the two, and the data shows it is more than capable of holding its own against a desktop part of that era. Neither chip is a winner across the board; the 2600K wins on frequency-sensitive workloads like Geekbench, while the 3720QM wins on Cinebench’s rendering tests.

Where Each One Wins

The i7-2600K is the choice for users prioritizing single-threaded responsiveness and workloads that reward raw clock speed. Its Geekbench single-core score of 768 is 5.8% higher than the 3720QM’s 726, and its multicore lead of 6.3% in Geekbench suggests it handles memory-latency-sensitive and bursty tasks better. The unlocked multiplier is a major advantage for enthusiasts who are willing to push the chip beyond its 3.80 GHz boost clock. The 2600K is also the better choice for desktop builds where the 95 W TDP is not a concern and where the Intel Socket 1155 platform offers upgrade flexibility.

The i7-3720QM wins the efficiency contest by a wide margin, consuming just 45 W versus 95 W. Its Cinebench victories, while small, are consistent across all three versions of the benchmark, indicating a slight IPC advantage from the newer 22 nm Ivy Bridge architecture. This makes it the better choice for sustained rendering workloads on a laptop, where the 2600K’s higher power draw would be impractical. The 3720QM also benefits from Intel HD 4000 graphics, which are a generation newer than the HD 3000 in the 2600K. For mobile users who need competent CPU performance without destroying battery life, the 3720QM is the clear winner. Its 6 MB of L3 cache is smaller, but the benchmark results show this does not translate into a performance deficit in the tested workloads. The 3720QM is the right pick for a laptop that needs to do serious work, while the 2600K is the right pick for a desktop that needs to be pushed to its limits.