Intel Core i5-2500K vs Intel Core i7-3820QM Comparison

Head-to-Head Benchmarks

The recorded data shows a clear split between Cinebench and Geekbench results, with each processor winning in different test families. The Intel Core i7-3820QM dominates the Cinebench suite, while the Intel Core i5-2500K takes both Geekbench tests.

In Cinebench R15 multicore, the i7-3820QM scores 481 against 354 for the i5-2500K, a 26.4% advantage. The pattern repeats in Cinebench R20 multicore: 2006 versus 1479, a 26.3% gap. Cinebench R23 multicore shows the same margin at 26.3%, with the i7 at 4777 and the i5 at 3523. Single-core Cinebench results follow suit. In R20 single-core, the i7 posts 283 versus 208, a 26.5% lead. R23 single-core sees 674 versus 497, again 26.3% in favor of the i7.

The i5-2500K fights back in Geekbench. In multicore, it scores 2434 against 2041 for the i7-3820QM, a 19.3% win. The single-core Geekbench result is even more decisive: 805 versus 601, a 33.9% margin for the i5. These are substantial reversals, not marginal differences.

Overall, the i7-3820QM wins 5 of 7 head-to-head tests, while the i5-2500K wins 2. The average benchmark score tells a similar story but with a much smaller gap: the i7 averages 1366, the i5 averages 1329, a difference of about 2.8%. Both processors sit near the 35th percentile of all CPUs in the database, with the i5 at 35 and the i7 at 36. Their nearest rivals reinforce this positioning. The i5-2500K trades within 0.6% of the Intel Core i5-4460S, Core i5-760, Celeron G6900T, and Celeron G6900E. The i7-3820QM sits within 0.3% of the Intel Xeon D-1521, Xeon E5-1410 v2, AMD Opteron 6376, and Core i5-8365UE.

Architecture Differences

The two chips come from different Intel process nodes and microarchitectures. The i5-2500K uses Sandy Bridge on a 32 nm process, while the i7-3820QM uses Ivy Bridge on a 22 nm process. Transistor counts differ accordingly: the i5 packs 1,160 million transistors on a 216 mm² die, the i7 packs 1,400 million on a smaller 160 mm² die. The die size reduction with more transistors reflects the process shrink.

Both are 4-core parts, but threading differs. The i5-2500K runs 4 threads total, one per core. The i7-3820QM runs 8 threads, using Hyper-Threading to double the thread count. This explains the Cinebench multicore advantage for the i7, as those workloads scale with thread availability. In contrast, the Geekbench results favor the i5 despite fewer threads, which suggests the i5's higher base clock matters more in those specific tests. The i5-2500K has a base clock of 3.30 GHz versus 2.70 GHz for the i7, while both boost to 3.70 GHz.

Cache configurations also differ. Both have 64 KB L1 and 256 KB L2 per core. The L3 cache is 6 MB shared on the i5 and 8 MB shared on the i7. The larger L3 helps the i7 in workloads that cycle through more data.

Integrated graphics differ as well. The i5-2500K includes Intel HD 3000, while the i7-3820QM includes Intel HD 4000. The i7 also has a much lower TDP: 45 watts versus 95 watts for the i5. That is a 50-watt gap, which reflects the mobile versus desktop design intent. The i5 uses Intel Socket 1155 and is a desktop part, while the i7 uses Intel BGA 1224 and is a mobile part. The i5 has an unlocked multiplier, the i7 does not. Memory support is DDR3 dual-channel for the i5, with 25.6 GB/s bandwidth. The i7 also has dual-channel memory, but the database does not list a bandwidth figure for it. The i5 supports PCIe Gen 2 with 16 lanes from the CPU; no PCIe data is recorded for the i7.

The Verdict

The data points to different use cases. If your priority is Cinebench-class rendering workloads, the i7-3820QM is the stronger choice. It wins every Cinebench test by roughly 26%, and the margin is consistent across R15, R20, and R23. The extra threads and larger L3 cache pay off in those multi-threaded render tasks. Single-core Cinebench also favors the i7, so even in lightly threaded render scenes it holds the edge.

If your priority is Geekbench-style system-level tests, the i5-2500K wins clearly. It leads by 19.3% in Geekbench multicore and by 33.9% in single-core. That is a large single-thread advantage, likely tied to the higher base clock and the older but higher-clocked design. For everyday responsiveness and legacy software that favors clock speed over thread count, the i5 is the better fit.

The i7-3820QM also offers a major efficiency advantage. Its 45 watt TDP is less than half the i5's 95 watt TDP, making it the obvious pick for thermally constrained systems like laptops or small-form-factor builds. The i5-2500K, with its unlocked multiplier, remains the choice for enthusiasts who want to overclock and are willing to accept higher power draw.

Neither processor is a clear overall winner. The i7 wins more tests and has a slightly higher average score, but the i5 wins the Geekbench family by large margins. The decision comes down to workload mix and platform constraints.

FAQ

Q: Which processor has the higher base clock speed?

A: The Intel Core i5-2500K has a base clock of 3.30 GHz, while the Intel Core i7-3820QM runs at 2.70 GHz. Both boost to 3.70 GHz.

Q: Does the i7-3820QM support more threads?

A: Yes. The i7-3820QM has 4 cores and 8 threads, while the i5-2500K has 4 cores and 4 threads.

Q: Which chip wins in Cinebench R23 multicore?

A: The i7-3820QM scores 4777 versus 3523 for the i5-2500K, a 26.3% advantage for the i7.

Q: Which chip wins in Geekbench single-core?

A: The i5-2500K scores 805 versus 601 for the i7-3820QM, a 33.9% lead for the i5.

Q: What is the TDP difference between the two?

A: The i5-2500K has a 95 watt TDP, while the i7-3820QM has a 45 watt TDP. The i7 draws less than half the power.

Q: Are both processors unlocked for overclocking?

A: No. The i5-2500K has an unlocked multiplier, but the i7-3820QM does not.

Where Each One Wins

The i7-3820QM wins in all Cinebench tests. That includes R15 multicore, R20 multicore and single-core, and R23 multicore and single-core. The margins are consistently around 26%. This makes it the better pick for rendering, video encoding, and other multi-threaded productivity workloads that behave like Cinebench. The 8 threads and 8 MB L3 cache provide the structural advantage.

The i5-2500K wins in both Geekbench tests. Its multicore lead is 19.3%, and its single-core lead is 33.9%. This suggests an advantage in system-level benchmarks that emphasize clock speed and per-core efficiency. For older software, light multitasking, or applications that do not scale well beyond 4 threads, the i5's higher base clock delivers better responsiveness.

The i7 also wins on efficiency. Its 45 watt TDP versus 95 watts for the i5 makes it the logical choice for battery-powered or thermally limited systems. The i5 wins on overclocking potential thanks to its unlocked multiplier, which the i7 lacks. If you need raw thread throughput and low power, choose the i7. If you need high single-thread speed and overclocking freedom, choose the i5.

Specification Differences

| Field | Intel Core i5-2500K | Intel Core i7-3820QM |

|---|---|---|

| Cores | 4 | 4 |

| Threads | 4 | 8 |

| Base Clock | 3.30 GHz | 2.70 GHz |

| Boost Clock | 3.70 GHz | 3.70 GHz |

| TDP | 95 W | 45 W |

| Socket | Intel Socket 1155 | Intel BGA 1224 |

| Architecture | Sandy Bridge | Ivy Bridge |

| Process Node | 32 nm | 22 nm |

| Transistors | 1,160 million | 1,400 million |

| Die Size | 216 mm² | 160 mm² |

| L1 Cache | 64 KB per core | 64 KB per core |

| L2 Cache | 256 KB per core | 256 KB per core |

| L3 Cache | 6 MB shared | 8 MB shared |

| Memory Support | DDR3 | Not specified |

| Memory Bus | Dual-channel | Dual-channel |

| Memory Bandwidth | 25.6 GB/s | Not specified |

| ECC Memory | No | No |

| PCIe | Gen 2, 16 Lanes (CPU only) | Not specified |

| Integrated Graphics | Intel HD 3000 | Intel HD 4000 |

| Market Segment | Desktop | Mobile |

| Multiplier Unlocked | Yes | No |

| Launch MSRP | $216 | Not specified |

The i5-2500K launches with a $216 MSRP; no launch MSRP is recorded for the i7-3820QM. The i5 is end-of-life, while production status for the i7 is not listed. Release dates differ by about a year: the i5 came out in January 2011, the i7 in April 2012. Part numbers are SR008 for the i5 and SR0MK for the i7.