Intel Core i7-2700K vs Intel Core i7-3820 Comparison

The Intel Core i7-3820 and Intel Core i7-2700K are both quad-core, eight-thread Sandy Bridge-era desktop processors, but they target different platforms and deliver measurably different performance. Benchmark data from Cinebench R15, R20, and R23 shows the i7-3820 winning every single head-to-head test, though by margins that are consistently narrow. The largest gap appears in Cinebench R15 multicore, where the i7-3820 scores 496 against the i7-2700K's 486, a 2.1% advantage. Single-core results mirror this pattern, with the i7-3820 leading by 1.5% in R15 (69 vs 68) and by 1.7% in R20 (291 vs 286). Across all six recorded benchmarks, the i7-3820's win margins range from 1.5% to 2.1%, with no test showing the i7-2700K ahead.

Head-to-Head Benchmarks

The most decisive victory for the Intel Core i7-3820 comes in Cinebench R15 multicore, where its 496-point score eclipses the i7-2700K's 486 by 2.1%. That same pattern holds in newer render workloads: Cinebench R20 multicore shows the i7-3820 scoring 2067 versus 2029, a 1.9% lead, and Cinebench R23 multicore shows 4923 versus 4833, again 1.9% ahead. The consistency is striking — across three generations of Cinebench, the multicore advantage never dips below 1.9%. This suggests the i7-3820's platform-level advantages translate into sustained throughput gains, not just a single synthetic spike.

Single-core results tell a similar story, though the margins are slightly tighter. In Cinebench R15 single-core, the i7-3820 scores 69 versus 68, a 1.5% edge. Cinebench R20 single-core sees the i7-3820 at 291 against 286, a 1.7% difference. The R23 single-core test repeats the 1.9% gap seen in multicore, with 695 versus 682. These single-core wins are notable because both CPUs share the same 32 nm process node and Sandy Bridge architecture; the i7-3820's higher base clock of 3.60 GHz versus 3.50 GHz likely contributes, though its boost clock is actually lower at 3.80 GHz versus 3.90 GHz on the i7-2700K.

The i7-3820's average benchmark score of 1424 places it in the 37th percentile of all CPUs, with its nearest rival being the Intel Xeon Bronze 3106 at 1422 (a 0.1% delta). The i7-2700K's average score of 1419 also sits at the 37th percentile, with its closest competitor being the AMD Opteron 4274 HE at 1420 (a 0% delta). Both processors occupy essentially the same performance tier relative to the broader market, but in direct comparison, the i7-3820 wins all six head-to-head matchups. There is no benchtest in the data where the i7-2700K takes the lead.

The Verdict

From the benchmark data alone, the Intel Core i7-3820 is the faster processor in every measured workload. It wins all six Cinebench tests, with margins that, while small (1.5% to 2.1%), are consistent across both single-threaded and multi-threaded scenarios. Users running Cinebench R15, R20, or R23 will see the i7-3820 finish ahead every time. However, the i7-2700K is not far behind — its scores trail by less than 2.1% in all cases, and its single-core results come within 1.5% to 1.9% of the i7-3820. The i7-2700K's higher boost clock of 3.90 GHz versus 3.80 GHz narrows the gap in lightly threaded tasks, but it is not enough to overcome the i7-3820's advantages.

The i7-3820 is the pick for users who prioritize maximum Cinebench throughput, whether in R15, R20, or R23. The i7-2700K makes sense only if the platform differences matter more than raw scores — it uses the Intel Socket 1155 with dual-channel memory, while the i7-3820 requires Intel Socket 2011 with quad-channel memory. Both are end-of-life products, and both sit at the 37th percentile of all CPUs, so neither is a performance outlier by modern standards. The data shows a clear winner in the i7-3820, but the margin is small enough that the i7-2700K remains a viable alternative for users already invested in its socket.

Architecture Differences

Both processors are built on Intel's 32 nm process and share the Sandy Bridge architecture, but they diverge significantly in platform design. The i7-3820 uses the Sandy Bridge-E codename and targets Intel Socket 2011, while the i7-2700K uses the standard Sandy Bridge codename on Intel Socket 1155. This platform split drives several key differences. The i7-3820 supports quad-channel DDR3 memory with a theoretical bandwidth of 51.2 GB/s, whereas the i7-2700K is limited to dual-channel DDR3 at 21.3 GB/s — a 2.4x bandwidth advantage for the i7-3820 that likely explains its multicore wins despite similar core counts.

Cache configurations also differ. The i7-3820 features 10 MB of shared L3 cache, while the i7-2700K has 8 MB. Both have identical L1 and L2 caches per core (64 KB and 256 KB respectively). The i7-3820 also brings more PCIe lanes: 40 lanes of PCIe Gen 2 from the CPU, versus 16 lanes on the i7-2700K. Transistor counts reflect the larger die — the i7-3820 packs 1,270 million transistors on a 294 mm² die, while the i7-2700K has 1,160 million on 216 mm². The i7-3820's TDP is higher at 130W versus 95W, a consequence of the larger platform and quad-channel memory controller.

Clock speeds are close but not identical. The i7-3820 runs a 3.60 GHz base and 3.80 GHz boost, while the i7-2700K runs 3.50 GHz base and 3.90 GHz boost. Both have unlocked multipliers, enabling overclocking, but the i7-2700K ships with an integrated GPU (Intel HD 3000) while the i7-3820 has no integrated graphics. Memory support is DDR3 for both, and neither supports ECC. The i7-2700K launched earlier (October 2011) with a $332 launch MSRP, while the i7-3820 arrived in February 2012 at a $305 launch MSRP.

FAQ

Q: Which processor is faster in Cinebench R23 multicore?

A: The Intel Core i7-3820 scores 4923 versus the i7-2700K's 4833, a 1.9% advantage for the i7-3820.

Q: Does the i7-2700K win any benchmark in the head-to-head data?

A: No. The i7-3820 wins all six recorded benchmarks, with wins in Cinebench R15, R20, and R23 for both single-core and multicore tests.

Q: What is the memory bandwidth difference between the two?

A: The i7-3820 supports quad-channel DDR3 with 51.2 GB/s theoretical bandwidth, while the i7-2700K uses dual-channel DDR3 at 21.3 GB/s.

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

A: Yes, both have 4 cores and 8 threads, and both are built on the 32 nm process node.

Q: Which processor has a higher boost clock?

A: The i7-2700K has a 3.90 GHz boost clock, while the i7-3820 boosts to 3.80 GHz. However, the i7-3820 has a higher base clock at 3.60 GHz versus 3.50 GHz.

Q: What is the average benchmark score for each?

A: The i7-3820 has an average benchmark score of 1424, and the i7-2700K has an average of 1419. Both sit in the 37th percentile of all CPUs.

Where Each One Wins

The i7-3820 wins every workload recorded in the benchmark data. Its largest margin is 2.1% in Cinebench R15 multicore (496 vs 486), and its smallest is 1.5% in Cinebench R15 single-core (69 vs 68). In the newer R20 and R23 tests, the i7-3820 consistently leads by 1.9% in multicore and 1.7% to 1.9% in single-core. This makes the i7-3820 the clear choice for Cinebench rendering tasks, where its quad-channel memory bandwidth and larger 10 MB L3 cache (versus 8 MB) provide a measurable edge.

The i7-2700K's advantages are not visible in the benchmark data, but platform traits differentiate it. It has a lower TDP of 95W versus 130W, which could make it easier to cool in a smaller system. It also includes integrated graphics (Intel HD 3000), so a discrete GPU is not strictly required. The i7-2700K's higher boost clock of 3.90 GHz gives it a theoretical edge in single-threaded bursts, but the data shows the i7-3820 still wins single-core tests by 1.5% to 1.9%. The i7-2700K's dual-channel memory and 16 PCIe lanes are more modest than the i7-3820's quad-channel and 40 lanes, making the i7-3820 better suited for memory-bandwidth-hungry or multi-GPU configurations.

For users on a Socket 1155 platform, the i7-2700K is the only one of the two that fits. For users building on Socket 2011, the i7-3820 offers superior benchmark scores across the board. The data does not show a single test where the i7-2700K outperforms the i7-3820, so the choice hinges on platform compatibility and power envelope rather than performance. The i7-3820 is the benchmark winner; the i7-2700K is the lower-power, integrated-graphics alternative.