Intel Core i7-3820 vs Intel Xeon E3-1225 v5 Comparison

Head-to-Head Benchmarks

The recorded data shows a clean sweep for the Intel Xeon E3-1225 v5 across all six Cinebench comparisons. The Xeon wins every single- and multi-threaded test, though the margins are relatively modest rather than decisive. In the multicore R15 test, the Xeon scores 510 against the Core i7-3820's 496, a 2.8% advantage. The single-core R15 result widens slightly, with the Xeon at 72 versus 69, a 4.3% lead, which is the largest delta in the entire comparison.

Moving to R20, the pattern holds. The Xeon posts a multicore score of 2127, while the i7-3820 manages 2067, a 2.9% gap. In single-core R20, the Xeon scores 300 against 291, representing a 3.1% edge. The R23 results mirror the R20 multicore delta exactly: the Xeon reaches 5065, the i7-3820 lands at 4923, and the difference is again 2.9%. The R23 single-core run shows the Xeon at 715 versus 695, another 2.9% margin.

What these numbers indicate is consistent, albeit narrow, superiority for the newer Skylake part. The Xeon wins all six head-to-head matchups, but the largest victory is just 4.3%. In practical terms, the performance gap is real but not transformative for most workloads. The average benchmark score for the Xeon is 1465, placing it at the 38th percentile among all CPUs, whereas the i7-3820 averages 1424, sitting at the 37th percentile. Both processors occupy a similar tier in the overall performance distribution.

The nearest rival data provides additional context. The Xeon's closest competitors include the Intel Core i3-7350K at 1462 (0.2% behind), the AMD Ryzen 3 PRO 2200GE at 1461 (0.3% behind), and the Intel Core i7-4710HQ at 1473 (0.5% ahead). The i7-3820's nearest rivals are the Intel Xeon Bronze 3106 at 1422 (0.1% behind), the Intel Core i5-4570S at 1426 (0.2% ahead), and the Intel Core i7-3720QM at 1421 (0.2% behind). These figures confirm that both chips are clustered tightly with their contemporary peers, and the head-to-head delta between them is comparable to the noise between adjacent rivals.

Architecture Differences

The two processors come from fundamentally different eras of Intel design. The Xeon E3-1225 v5 is built on the Skylake architecture (Skylake-DT codename) using a 14 nm process node, while the Core i7-3820 uses the Sandy Bridge architecture (Sandy Bridge-E codename) on a 32 nm node. This generational gap explains several key differences. The Xeon packs 1,750 million transistors into a 122 mm² die, whereas the i7-3820 contains 1,270 million transistors across a substantially larger 294 mm² die. The denser 14 nm process allows the Xeon to fit more transistors in less than half the physical area.

Core and thread counts differ as well. Both chips have four physical cores, but the i7-3820 supports Hyper-Threading, giving it eight threads total. The Xeon E3-1225 v5 is limited to four threads, meaning it lacks simultaneous multithreading. Despite this apparent disadvantage, the Xeon still manages to outperform the i7-3820 in every multi-threaded benchmark, which speaks to the efficiency of the Skylake architecture and its newer instruction pipeline.

Cache hierarchies also diverge. Both allocate 64 KB of L1 and 256 KB of L2 per core. However, the i7-3820 has a larger shared L3 cache at 10 MB, while the Xeon offers 8 MB. The older chip's larger cache does not translate into a performance win in the recorded benchmarks. Memory support shows a notable split: the Xeon supports both DDR3 and DDR4 in a dual-channel configuration, yielding 34.1 GB/s of memory bandwidth. The i7-3820 supports only DDR3 but uses a quad-channel bus, delivering 51.2 GB/s. The i7-3820's memory bandwidth advantage is substantial, yet it does not overcome the Xeon's architectural efficiency in the Cinebench workloads.

PCIe capabilities differ as well. The Xeon provides PCIe Gen 3 with 16 lanes, while the i7-3820 offers PCIe Gen 2 with 40 lanes. The newer standard on the Xeon trades lane count for higher per-lane throughput. Integrated graphics are present only on the Xeon, which includes HD Graphics P530; the i7-3820 has no integrated graphics. This is consistent with their market segments: the Xeon targets server and workstation deployments where basic display output can be useful, while the i7-3820 is a desktop part that assumes a discrete graphics card. The Xeon also supports ECC memory, a feature absent on the i7-3820, and it carries an unlocked multiplier on the i7-3820, while the Xeon's multiplier remains locked.

FAQ

Q: Which processor is faster in single-threaded workloads?

A: The Intel Xeon E3-1225 v5 wins every single-core test. It leads by 4.3% in Cinebench R15 (72 vs 69), by 3.1% in R20 (300 vs 291), and by 2.9% in R23 (715 vs 695).

Q: Does the Core i7-3820's extra threads give it a multicore advantage?

A: No. Despite having eight threads versus the Xeon's four, the i7-3820 loses all three multicore tests. The Xeon leads by 2.8% in R15 (510 vs 496), 2.9% in R20 (2127 vs 2067), and 2.9% in R23 (5065 vs 4923).

Q: How do these chips compare to their closest rivals?

A: The Xeon E3-1225 v5 averages 1465 and sits within 0.6% of its nearest competitors, including the Xeon E3-1515M v5 at 1456 and the Core i7-4710HQ at 1473. The i7-3820 averages 1424 and is within 0.3% of rivals like the Xeon Bronze 3106 at 1422 and the Core i7-3720QM at 1421.

Q: What are the memory bandwidth differences?

A: The i7-3820 has a quad-channel DDR3 bus delivering 51.2 GB/s, while the Xeon uses dual-channel DDR3 or DDR4 at 34.1 GB/s. The i7-3820 offers roughly 50% more memory bandwidth on paper, yet it still trails in all recorded benchmarks.

Q: Do both processors support ECC memory?

A: No. ECC memory support is present on the Xeon E3-1225 v5 but absent on the Core i7-3820. This aligns with the Xeon's server/workstation positioning versus the i7's desktop role.

Q: Which chip has integrated graphics?

A: Only the Xeon E3-1225 v5 includes integrated graphics, specifically HD Graphics P530. The Core i7-3820 has no integrated graphics and requires a discrete GPU for display output.

Specification Differences

The two processors differ across nearly every major specification category. The Xeon E3-1225 v5 operates with a base clock of 3.30 GHz and a boost clock of 3.70 GHz, while the i7-3820 starts higher at 3.60 GHz base and boosts to 3.80 GHz. The i7-3820 has higher clock speeds, yet the Xeon wins all benchmarks. Thermal design power also diverges sharply: the Xeon is rated at 80 W, while the i7-3820 draws 130 W, a 62.5% higher power envelope for the older chip.

Sockets are incompatible. The Xeon uses Intel Socket 1151, and the i7-3820 uses Intel Socket 2011. Process technology differs by a full generation node: 14 nm for the Xeon versus 32 nm for the i7-3820. Transistor counts reflect the process gap: 1,750 million for the Xeon versus 1,270 million for the i7-3820. Die size favors the Xeon at 122 mm² versus the i7-3820's 294 mm². L3 cache is larger on the i7-3820 at 10 MB shared, compared to the Xeon's 8 MB shared.

Memory support shows the Xeon accepting both DDR3 and DDR4, while the i7-3820 is limited to DDR3. Memory bus width also differs: dual-channel on the Xeon, quad-channel on the i7-3820. Memory bandwidth is 34.1 GB/s for the Xeon and 51.2 GB/s for the i7-3820. PCIe generation and lane counts differ: Gen 3 with 16 lanes for the Xeon, Gen 2 with 40 lanes for the i7-3820. ECC memory is supported only on the Xeon. Integrated graphics exist only on the Xeon (HD Graphics P530); the i7-3820 has none. The market segment is server/workstation for the Xeon and desktop for the i7-3820. The multiplier is unlocked on the i7-3820 but locked on the Xeon. The Xeon's launch MSRP was $224, while the i7-3820 launched at $305. Release dates are separated by several years: the Xeon arrived in October 2015, while the i7-3820 debuted in February 2012.

The Verdict

The benchmark data is unambiguous: the Intel Xeon E3-1225 v5 outperforms the Intel Core i7-3820 in every recorded test, from single-core R15 to multicore R23. The margins are consistent, ranging from 2.8% to 4.3%, and the Xeon wins all six head-to-head matchups. The i7-3820's advantages in paper specifications, namely its higher clock speeds, larger L3 cache, quad-channel memory, and additional threads, do not translate into any measured performance win. The Skylake architecture's efficiency on the 14 nm process overcomes these deficits.

For workloads that rely on single-threaded performance, the Xeon is clearly the better choice. Its 4.3% lead in R15 single-core and 3.1% lead in R20 single-core indicate superior per-clock execution. Even in multicore scenarios where the i7-3820 can leverage eight threads, the Xeon still leads by roughly 3% across the board. This suggests that the Xeon's architectural improvements more than compensate for its lack of Hyper-Threading.

The Xeon also carries practical advantages for specific use cases. ECC memory support makes it suitable for error-sensitive server or workstation tasks. Integrated graphics provide a fallback for basic display needs without a discrete GPU. The lower 80 W TDP means less thermal output and potentially lower cooling requirements. The i7-3820, by contrast, offers an unlocked multiplier for enthusiast overclocking, a feature the Xeon lacks, and its quad-channel memory delivers higher theoretical bandwidth, though this does not show up as a performance benefit in the recorded Cinebench results.

The performance percentiles place both chips close together: 38th for the Xeon and 37th for the i7-3820. The average benchmark scores, 1465 versus 1424, represent a 2.9% gap, consistent with the head-to-head deltas. Neither processor is a standout in the broader CPU landscape, but within this pairing, the Xeon E3-1225 v5 is the superior part across every measurable dimension in the database. Users seeking maximum performance from these two options should select the Xeon; those who value overclocking flexibility or quad-channel memory bandwidth may still consider the i7-3820, but the data does not show any workload where it wins.