Intel Core i7-7820HK vs Intel Xeon E3-1275 v5 Comparison

The Intel Core i7-7820HK and Intel Xeon E3-1275 v5 are both 4-core, 8-thread processors from Intel, but they target fundamentally different market segments: mobile computing versus server/workstation platforms. Despite their architectural kinship, the benchmark data reveals a consistent performance gap favoring the Xeon part across every single test in the head-to-head comparison.

Head-to-Head Benchmarks

The data is unambiguous: the Intel Xeon E3-1275 v5 wins all six head-to-head benchmark comparisons against the Core i7-7820HK. The margins are remarkably consistent, hovering just under 11 percent across all tests. In Cinebench R15 multi-core, the Xeon scores 712 against the i7's 635, a delta of -10.8 percent for the i7. The single-core R15 test shows a similar pattern, with the Xeon at 100 and the i7 at 89, a -11 percent difference.

Moving to newer workloads, the story remains unchanged. Cinebench R20 multi-core sees the Xeon at 2967 versus the i7's 2648, again a -10.8 percent delta. The single-core R20 results show 418 for the Xeon versus 373 for the i7. In the most demanding test, Cinebench R23, the Xeon scores 7065 multi-core and 997 single-core, while the i7 manages 6306 and 890 respectively. Both R23 deltas sit at -10.7 percent for the i7.

These results indicate that the Xeon E3-1275 v5 holds a decisive, uniform advantage of roughly 11 percent across all workloads tested, whether single-threaded or multi-threaded. This consistency suggests a fundamental clock-speed advantage rather than any architectural superiority in IPC. The average benchmark scores corroborate this: the i7-7820HK averages 2048 across its benchmark suite, while the Xeon averages 2043, a negligible 0.2 percent difference that places them in the same performance tier overall, despite the Xeon's win in every direct head-to-head test.

Architecture Differences

Both processors are built on Intel's 14 nm process node, but they belong to different architectural generations. The Core i7-7820HK uses the Kaby Lake architecture (codename Kaby Lake-H), while the Xeon E3-1275 v5 is based on the older Skylake architecture (codename Skylake-DT). This generation gap explains some of the feature differences, though not the performance gap, as the newer Kaby Lake part actually loses in every benchmark.

The core configurations are identical: 4 cores, 8 threads, 64 KB of L1 cache per core, 256 KB of L2 cache per core, and 8 MB of shared L3 cache. The Xeon has a slight die-size advantage at 122 mm² versus the i7's 126 mm², and the Xeon's transistor count is listed at 1,750 million. Clock speeds are where the Xeon pulls ahead: it runs at a 3.60 GHz base clock and 4.00 GHz boost clock, compared to the i7's 2.90 GHz base and 3.90 GHz boost. This 700 MHz base-clock advantage and 100 MHz boost advantage directly translate into the consistent benchmark deltas observed.

The platform differences are substantial. The i7-7820HK is a mobile part using the Intel BGA 1440 socket with a 45 W TDP, while the Xeon uses the desktop Intel Socket 1151 with an 80 W TDP. The Xeon supports ECC memory, which the i7 does not, and lists a memory bandwidth of 34.1 GB/s. Both support DDR3 and DDR4 memory in dual-channel configurations and offer PCIe Gen 3 with 16 lanes from the CPU. Integrated graphics differ: the i7 features Intel HD Graphics 630, while the Xeon has HD Graphics P530. The i7's multiplier is unlocked, enabling overclocking, whereas the Xeon's is locked. The i7 was released in January 2017 with a launch MSRP of $378; the Xeon launched in October 2015 at $350. Both parts are now end-of-life. The i7 belongs to the Core i7 (Kaby Lake-H) generation, while the Xeon is from the Xeon E3 (Skylake-DT) generation.

Where Each One Wins

Based strictly on the benchmark data, the Xeon E3-1275 v5 wins in every measured category. It takes all six head-to-head benchmark victories, with wins in both single-core and multi-core tests across Cinebench R15, R20, and R23. The uniform ~11 percent margin means the Xeon is consistently faster for any workload that relies on raw CPU computation, whether lightly threaded or fully parallel.

The Core i7-7820HK, despite losing every direct comparison, has its own advantages that are not captured in the CPU benchmarks. Its 45 W TDP is nearly half the Xeon's 80 W TDP, making it far more suitable for power-constrained mobile environments. The unlocked multiplier offers overclocking headroom, which the locked Xeon cannot provide. The i7 also carries the newer Kaby Lake architecture, though this does not translate into a performance win in the tested workloads.

It is notably the average benchmark scores place these two processors within 0.2 percent of each other overall, with the i7 at 2048 and the Xeon at 2043. This means that outside the specific Cinebench tests, the overall performance picture is essentially a tie. The nearest rivals for the i7 include the Intel Xeon E3-1270 v5 at a 0 percent delta, the AMD Ryzen 5 7520U at 0.1 percent, and the AMD Ryzen 3 3100 at -0.3 percent. The Xeon's nearest rivals include the same Ryzen 5 7520U at -0.1 percent, the Intel Core i7-7700T at 0.2 percent, and the AMD Opteron 6386 SE at 0.3 percent.

The Verdict

The data points decisively toward the Intel Xeon E3-1275 v5 for anyone prioritizing peak CPU performance in the tested workloads. It wins every head-to-head benchmark by approximately 11 percent, a substantial and consistent margin that holds across both single-threaded and multi-threaded applications. The Xeon's higher base and boost clocks, combined with its ECC memory support, make it the superior choice for server or workstation deployments where stability and throughput are paramount.

The Core i7-7820HK, however, serves a different purpose. Its 45 W TDP makes it viable for mobile platforms, and the unlocked multiplier offers flexibility for enthusiasts willing to overclock. The i7's average benchmark score of 2048 is marginally higher than the Xeon's 2043, suggesting that in a broader benchmark suite, the i7 might close the gap or even edge ahead. The Xeon's percentile ranking of 45 versus the i7's 46 also indicates they sit at essentially the same level in the overall CPU landscape.

For a desktop or server build where power consumption is not a primary concern, the Xeon E3-1275 v5 is the clear winner based on benchmark data. For a laptop or compact mobile system, the i7-7820HK is the only viable option between the two given its BGA 1440 socket and lower TDP. The choice ultimately hinges on platform requirements rather than raw performance, since the Xeon demonstrably outperforms the i7 in every direct test.

FAQ

Q: Which processor is faster in multi-core workloads?

A: The Intel Xeon E3-1275 v5 wins all three multi-core Cinebench tests. In R15, it scores 712 versus 635; in R20, 2967 versus 2648; and in R23, 7065 versus 6306. The margin is approximately 10.8 percent in each case.

Q: How do the clock speeds compare between the two CPUs?

A: The Xeon E3-1275 v5 has a 3.60 GHz base clock and 4.00 GHz boost clock. The Core i7-7820HK has a 2.90 GHz base clock and 3.90 GHz boost clock. The Xeon's higher clocks explain its consistent benchmark advantage.

Q: Do both processors support ECC memory?

A: No. The Xeon E3-1275 v5 supports ECC memory, while the Core i7-7820HK does not. This is a key differentiator for server and workstation reliability requirements.

Q: What are the TDP ratings for each chip?

A: The Core i7-7820HK has a 45 W TDP, making it suitable for mobile platforms. The Xeon E3-1275 v5 has an 80 W TDP, which is typical for a desktop server/workstation part.

Q: Are these processors still in production?

A: Both are end-of-life. The Core i7-7820HK was released in January 2017 with a launch MSRP of $378. The Xeon E3-1275 v5 was released in October 2015 with a launch MSRP of $350.

Q: How does the overall benchmark average compare?

A: The Core i7-7820HK has an average benchmark score of 2048, while the Xeon E3-1275 v5 averages 2043. This is a 0.2 percent difference, placing them in the same performance tier despite the Xeon's wins in direct comparisons.