Intel Core i7-3720QM vs Intel Core i7-3840QM Comparison

The Intel Core i7-3720QM and Intel Core i7-3840QM are two closely matched Ivy Bridge mobile processors, both aimed at high-performance laptops from the 2012 era. The data shows a clear split: the i7-3840QM takes a decisive lead across the Cinebench suite, while the i7-3720QM counters with surprisingly strong Geekbench results. This makes the choice between them less about raw generational superiority and more about which benchmark suite aligns with your specific workload.

Head-to-Head Benchmarks

The most striking pattern in the head-to-head data is the complete reversal of fortunes between the Cinebench and Geekbench tests. The Intel Core i7-3840QM wins six of the eight benchmark comparisons, but the Intel Core i7-3720QM wins the two that matter most for certain productivity tasks.

Looking at Cinebench first, the i7-3840QM is consistently faster by a narrow but uniform margin. In Cinebench R15 multi-core, the i7-3840QM scores 498 against the i7-3720QM's 475, a delta of -4.6% (negative indicating the i7-3720QM trails). The single-core R15 test shows a similar gap: 70 versus 66, a -5.7% difference. Moving to Cinebench R20, the i7-3840QM posts 2079 multi-core and 293 single-core, while the i7-3720QM manages 1981 and 279 respectively – deltas of -4.7% and -4.8%. The R23 results mirror this exactly: 4952 vs 4718 multi-core and 699 vs 666 single-core, both at -4.7%. This consistency across three generations of Cinebench suggests a stable, clock-driven advantage for the i7-3840QM rather than any workload-specific quirk.

Then comes Geekbench, where the tables turn dramatically. The i7-3720QM scores 2457 in multi-core versus the i7-3840QM's 2111 – a 16.4% lead. Single-core Geekbench shows an even larger proportional gap: 726 versus 628, a 15.6% advantage. These are not marginal wins; they represent a substantial performance reversal. The data indicates that whatever the Geekbench workload is doing, it favors the i7-3720QM's configuration to a degree that overshadows the clock speed differences.

Interpreting these results requires caution. The i7-3840QM's wins are narrow, hovering around 4.6-5.7% across all Cinebench tests. The i7-3720QM's wins are broad, at 15.6-16.4% in Geekbench. If you average the benchmark scores, the two chips land nearly identical: the i7-3720QM averages 1421, and the i7-3840QM averages 1416. That 5-point difference is negligible. The percentile ranking for both is 37, placing them in the same tier of overall CPU performance. What this tells a builder is that neither chip is a clear winner on aggregate; the choice hinges on which benchmark reflects your actual software.

FAQ

Q: Which processor wins more benchmark comparisons?

A: The Intel Core i7-3840QM wins 6 out of 8 head-to-head tests. The Intel Core i7-3720QM wins the remaining 2, which are both Geekbench tests.

Q: How much faster is the i7-3840QM in Cinebench R23 multi-core?

A: The i7-3840QM scores 4952 versus the i7-3720QM's 4718, a 4.7% advantage. This pattern holds across R15, R20, and R23 multi-core tests.

Q: Why does the i7-3720QM win Geekbench?

A: The data shows a 16.4% lead in multi-core (2457 vs 2111) and a 15.6% lead in single-core (726 vs 628). The cause is not specified in the benchmark data, but the magnitude suggests a workload-specific advantage.

Q: Are the average benchmark scores similar?

A: Yes. The i7-3720QM has an average benchmark score of 1421, and the i7-3840QM has an average of 1416. Both processors rank at the 37th percentile of all CPUs.

Q: Which chip has a higher boost clock?

A: The Intel Core i7-3840QM has a boost clock of 3.80 GHz, compared to 3.60 GHz for the i7-3720QM.

Q: Do both processors have the same core and thread counts?

A: Yes, both have 4 cores and 8 threads, and both have a 45 W TDP.

Architecture Differences

At the architectural level, these two processors are nearly identical, which explains their similar performance envelopes. Both are built on Intel's Ivy Bridge architecture using a 22 nm process node, fabricated by Intel. The transistor count is the same at 1,400 million, and the die size is identical at 160 mm². The codename for both is Ivy Bridge, and their generation is listed identically as Core i7 (Ivy Bridge).

The only meaningful architectural difference is the L3 cache. The i7-3720QM has 6 MB of shared L3 cache, while the i7-3840QM has 8 MB. That extra 2 MB of cache is the primary on-die differentiator between the two. Both share the same L1 cache at 64 KB per core and L2 cache at 256 KB per core. The integrated graphics are the same Intel HD 4000, and both support dual-channel memory. Neither supports ECC memory, and both are locked (multiplier unlocked: false).

The release dates differ: the i7-3720QM launched on 2012-04-28, and the i7-3840QM followed on 2012-09-02. This five-month gap likely allowed Intel to bin higher-quality dies for the later chip, which would explain the cache increase and higher clock speeds. The part numbers also differ – SR0MM for the i7-3720QM and SR0UU for the i7-3840QM – confirming they are distinct silicon revisions.

Specification Differences

The specification table shows exactly where these two chips diverge. The base clock is the most obvious difference: the i7-3840QM runs at 2.80 GHz versus 2.60 GHz for the i7-3720QM. The boost clock follows the same pattern, with the i7-3840QM hitting 3.80 GHz compared to 3.60 GHz. Both stay within a 45 W TDP, meaning the higher clocks do not come at a thermal cost.

The L3 cache is the other key difference: 8 MB shared on the i7-3840QM versus 6 MB shared on the i7-3720QM. All other specifications match perfectly – 4 cores, 8 threads, dual-channel memory bus, Intel HD 4000 graphics, Intel BGA 1224 socket, and the 22 nm process. The i7-3840QM lists DDR3 memory support in its specification, while the i7-3720QM's memory support field is null; however, both use a dual-channel memory bus.

Neither chip has an unlocked multiplier, so overclocking is not an option on either. Both are mobile segment parts, and neither has a launch MSRP listed in the data. The release dates differ by roughly five months, which is worth noting for anyone tracking production timelines.

Where Each One Wins

Based strictly on benchmark wins, the use-case split is clear. The i7-3840QM is the better choice for Cinebench-style workloads, which typically represent rendering and 3D modeling tasks. Its 4.6-5.7% advantage across R15, R20, and R23 multi-core and single-core tests makes it the more capable chip for CPU-bound creative work. If your software relies on rendering engines similar to Cinebench, the i7-3840QM will finish jobs measurably faster.

The i7-3720QM wins in Geekbench, which is a more general-purpose benchmark covering a wider range of tasks including integer, floating-point, and memory operations. Its 15.6-16.4% lead is substantial, suggesting that for everyday productivity, web browsing, and office applications, the i7-3720QM may actually feel snappier despite its lower clock speeds. This is counterintuitive but the data supports it.

For gaming, neither chip has a clear edge from the benchmark data alone. Both use the same Intel HD 4000 integrated graphics, and their Cinebench and Geekbench scores are close enough in aggregate (1421 vs 1416) that you would not notice a difference in most titles. The i7-3840QM's cache advantage might help in some simulation-heavy games, but the Geekbench deficit suggests it is not a universal benefit.

The i7-3840QM also wins on paper for multi-threaded production work due to the higher clocks and larger cache, even though the benchmark deltas are small. If you are building a laptop for video editing or 3D rendering, the i7-3840QM is the safer bet. If you prioritize responsiveness in general computing, the i7-3720QM's Geekbench dominance makes it a legitimate alternative.

The Verdict

The data does not crown a single winner here. The Intel Core i7-3840QM takes the majority of benchmark wins, but its margins are modest – never exceeding 5.7%. The Intel Core i7-3720QM loses in raw count but wins decisively in Geekbench, with margins over 15%. Both sit at the 37th percentile of all CPUs, and their average benchmark scores differ by just 0.4%. This is a statistical tie in aggregate.

Choose the i7-3840QM if your primary workloads are rendering, multi-threaded compilation, or any task that scales with Cinebench performance. The 4.7% advantage in R23 multi-core (4952 vs 4718) is real and will compound over long render times. The extra 2 MB of L3 cache and higher boost clock are physical advantages that show up consistently across all three Cinebench versions.

Choose the i7-3720QM if you value Geekbench performance, which correlates with a broader range of everyday tasks. Its 16.4% multi-core and 15.6% single-core leads are too large to ignore, even if they appear in only one benchmark suite. For a general-purpose laptop that will handle office work, web apps, and light productivity, the i7-3720QM may deliver a better day-to-day experience.

Ultimately, both chips are from the same generation, same architecture, and same process node. The i7-3840QM is a higher-binned, later-released variant with more cache and higher clocks. The i7-3720QM's Geekbench wins suggest that its memory subsystem or some other unspecified characteristic compensates for those deficits. If you must pick one for a build, match the chip to your software. If you are unsure, the i7-3840QM's broader win count makes it the default recommendation.