Intel Core i7-5820K vs Intel Xeon E5-4620 v3 Comparison

The Intel Xeon E5-4620 v3 and the Intel Core i7-5820K are both Haswell-era parts on the Intel Socket 2011-3 platform, but they target very different corners of the market. The Xeon is a 10-core server/workstation chip with a 105W TDP, while the i7 is a 6-core desktop part with a 140W TDP and an unlocked multiplier. The benchmark data shows a consistent, if modest, victory for the Xeon across all tested Cinebench workloads, despite the i7's higher clock speeds and lower core count.

Head-to-Head Benchmarks

The Xeon E5-4620 v3 wins all six head-to-head benchmark comparisons, but the margin is remarkably uniform. In Cinebench R15 multi-core, the Xeon scores 901 against the i7-5820K's 841, a 7.1% delta. The single-core R15 test shows a similar story: 127 for the Xeon versus 118 for the i7, a 7.6% advantage. This is the largest single-core lead the Xeon manages, and it is telling that a lower-clocked server chip beats a desktop part in a single-threaded test.

Moving to Cinebench R20, the pattern holds. The Xeon's multi-core score is 3757, while the i7-5820K manages 3508, again a 7.1% delta. Single-core R20 results are 530 for the Xeon and 495 for the i7, a 7.1% gap. The R23 results repeat the same trend: the Xeon leads 8946 to 8354 in multi-core and 1263 to 1179 in single-core, both with a 7.1% delta. The consistency of that 7.1% figure across multiple tests suggests a fundamental performance advantage that scales evenly across all thread counts.

It is notably the i7-5820K has a separate Geekbench result in its own benchmark list, scoring 5464 multi-core and 1174 single-core, but the Xeon has no Geekbench data in the head-to-head comparison, so no direct comparison is possible there. The i7's average benchmark score across all its tests is 2642, placing it in the 49th percentile of all CPUs. The Xeon's average score is 2587, also in the 49th percentile. The i7's nearest rival is the Intel Xeon E-2274G, with a delta of 0%, while the Xeon's closest competitor is the Intel Xeon E-2174G, also at a 0% delta. Both chips sit in a crowded mid-pack of performance, but the head-to-head data clearly favors the Xeon.

FAQ

Q: Which CPU is faster in multi-threaded workloads?

A: The Intel Xeon E5-4620 v3 wins every multi-core benchmark tested. In Cinebench R23 multi-core, it scores 8946 versus the i7-5820K's 8354, a 7.1% lead. The advantage is consistent across R15 (901 vs 841) and R20 (3757 vs 3508).

Q: Is the i7-5820K faster in single-threaded tasks due to its higher clock speed?

A: No. Despite a base clock of 3.30 GHz and boost clock of 3.60 GHz, the i7-5820K loses every single-core test. The Xeon E5-4620 v3, with its 2.00 GHz base and 2.60 GHz boost, leads in Cinebench R15 (127 vs 118), R20 (530 vs 495), and R23 (1263 vs 1179).

Q: Do these CPUs support the same memory features?

A: No. Both support DDR4 memory over a quad-channel bus, but the Xeon E5-4620 v3 supports ECC memory, while the i7-5820K does not. The i7 has a higher theoretical memory bandwidth at 68.3 GB/s, versus the Xeon's 59.7 GB/s.

Q: What are the PCIe lane differences?

A: The Xeon E5-4620 v3 provides 40 PCIe Gen 3 lanes (CPU only), while the i7-5820K provides 28 PCIe Gen 3 lanes (CPU only). This makes the Xeon more suitable for multi-GPU or heavy expansion configurations.

Q: Which chip has more cache?

A: The Xeon E5-4620 v3 has 25 MB of shared L3 cache, while the i7-5820K has 15 MB. Both have 64 KB of L1 and 256 KB of L2 per core.

Q: Are these CPUs overclockable?

A: Only the i7-5820K has an unlocked multiplier, making it overclockable. The Xeon E5-4620 v3's multiplier is locked, so its 2.00 GHz base clock is not adjustable through standard multiplier changes.

Architecture Differences

Both processors are built on Intel's 22 nm process node, fabricated by Intel, with identical transistor counts of 2,600 million and the same die size of 356 mm². They share the Haswell microarchitecture, but the codenames differ: the Xeon uses Haswell-EP, while the i7 uses Haswell-E. This distinction is significant. Haswell-EP is designed for scalability and reliability in server environments, which is why the Xeon supports ECC memory and offers 40 PCIe lanes. Haswell-E is a desktop derivative, optimized for consumer performance and overclocking, hence the unlocked multiplier on the i7.

The core counts are the most glaring architectural difference. The Xeon packs 10 cores and 20 threads, while the i7 has 6 cores and 12 threads. This explains the Xeon's multi-threaded advantage despite its much lower clock speeds. The cache hierarchy also reflects this: the Xeon's 25 MB of shared L3 cache is substantially larger than the i7's 15 MB, giving the server chip more room to hold working sets for its additional cores.

The memory support is another architectural divergence. Both use quad-channel DDR4, but the Xeon's ECC capability is a key server feature absent on the i7. The i7 counters with a higher memory bandwidth rating of 68.3 GB/s against the Xeon's 59.7 GB/s, likely due to higher supported memory speeds or timings on the consumer platform. The PCIe lane allocation also differs, with the Xeon offering 40 lanes versus the i7's 28, a direct consequence of the server-oriented design versus the consumer desktop focus.

Specification Differences

The two CPUs differ on nearly every major specification. The Xeon E5-4620 v3 has 10 cores and 20 threads, while the i7-5820K has 6 cores and 12 threads. Clock speeds are reversed: the Xeon runs at 2.00 GHz base and 2.60 GHz boost, while the i7 runs at 3.30 GHz base and 3.60 GHz boost. The TDP reflects this, with the i7 drawing 140W against the Xeon's 105W, an unusual inversion where the lower-clocked server chip is more power-efficient.

The L3 cache is 25 MB on the Xeon versus 15 MB on the i7, while L1 and L2 are identical at 64 KB and 256 KB per core, respectively. Memory bandwidth favors the i7 at 68.3 GB/s versus 59.7 GB/s. ECC memory support is exclusive to the Xeon. PCIe lanes favor the Xeon at 40 versus the i7's 28. The i7 has an unlocked multiplier, while the Xeon's is locked. The i7 is a desktop part, released on 2014-08-31, while the Xeon is a server/workstation part released on 2015-05-31. The Xeon has a launch MSRP of $1668, while the i7 has no launch MSRP listed. Both are end-of-life products.

Where Each One Wins

The Xeon E5-4620 v3 wins every benchmark in the head-to-head comparison, making its case straightforward: it is the better performer in both multi-core and single-core Cinebench tests. For workloads that scale across many threads, such as rendering, scientific computing, or heavy virtualization, the 10-core/20-thread configuration with 25 MB of L3 cache is clearly superior. Its ECC memory support and 40 PCIe lanes also make it the only choice among these two for a server or workstation that demands data integrity and high expansion capacity. The 105W TDP is a bonus, making it easier to cool than the i7 despite having more cores.

The i7-5820K's only theoretical wins come from unlisted metrics. Its higher memory bandwidth of 68.3 GB/s could benefit memory-bandwidth-sensitive applications, and its higher base and boost clocks might help in lightly threaded tasks if the Xeon's architectural advantage were not so pronounced. In practice, the benchmark data shows the i7 loses all single-core tests too. However, the i7's unlocked multiplier is a significant differentiator for enthusiasts who plan to overclock. A heavily overclocked i7 could potentially close the gap in multi-core workloads and surpass the Xeon in single-core performance, though the data provided does not include any overclocked results. For a desktop user who values tweaking and does not need ECC or 40 PCIe lanes, the i7 offers that flexibility.

The Verdict

The data is unambiguous: the Intel Xeon E5-4620 v3 outperforms the Intel Core i7-5820K in every measured benchmark, with a consistent 7.1% lead in most tests and a 7.6% lead in R15 single-core. If the choice is purely about stock performance, the Xeon is the better CPU. Its 10 cores, 20 threads, larger 25 MB L3 cache, ECC memory support, and 40 PCIe lanes make it a more capable and flexible processor for server, workstation, and high-end multi-threaded desktop workloads.

The i7-5820K's case rests entirely on its unlocked multiplier and its higher memory bandwidth. For a builder who intends to overclock aggressively and does not require ECC or the extra PCIe lanes, the i7 can be a compelling pick. Its 140W TDP suggests headroom for higher clocks, and its desktop heritage means it is designed for that kind of tuning. The i7's higher base clock of 3.30 GHz also makes it more responsive out of the box in lightly threaded tasks, even if the benchmarks do not reflect that advantage.

For a pure performance-per-core comparison, the i7 might have an edge if overclocked, but the stock data does not support it. The Xeon wins the head-to-head outright. The Xeon's launch MSRP of $1668 is higher, but that is a server pricing tier. Ultimately, the choice comes down to the platform: if you need server features like ECC and 40 PCIe lanes, the Xeon is the only option. If you are building a desktop rig and plan to overclock, the i7-5820K offers that capability, but you will be trading away the Xeon's core count and cache advantage. The benchmark results favor the Xeon E5-4620 v3 as the stronger stock processor.