Intel Core i7-3740QM vs Intel Xeon D-1521 Comparison

The Intel Xeon D-1521 and Intel Core i7-3740QM are both 4-core, 8-thread processors with a 45 W TDP, but they target entirely different segments of the market. The Xeon D-1521 is a server/workstation part built on Broadwell, while the i7-3740QM is a mobile processor from the Ivy Bridge generation. Benchmark data shows the i7-3740QM winning all six head-to-head Cinebench tests, though by narrow margins, while the Xeon D-1521 counters with server-oriented features like ECC memory support and a newer 14 nm process node. The following analysis breaks down where each processor excels, their architectural differences, and what the benchmark scores actually mean for potential use cases.

Where Each One Wins

The benchmark results are unambiguous: the Core i7-3740QM wins every single head-to-head test. Across six Cinebench runs covering R15, R20, and R23 in both single-core and multi-core modes, the i7-3740QM consistently outperforms the Xeon D-1521 by roughly 2.7% to 2.9%. The smallest margin is in Cinebench R15 multi-core, where the i7 scores 489 against the Xeon's 476, a 2.7% difference. The largest margin is in Cinebench R15 single-core, where the i7 leads 69 to 67, a 2.9% gap. This pattern holds steady across all tests, suggesting a consistent clock-speed advantage rather than any workload-specific strength.

The Xeon D-1521 does not win a single benchmark in the head-to-head comparison. However, its wins come from features not captured in Cinebench scores. The Xeon supports ECC memory, a critical feature for server reliability, while the i7-3740QM does not. The Xeon also supports both DDR3 and DDR4 memory, whereas the i7's memory support is not specified in the data. For workloads that require error-correcting memory or newer memory standards, the Xeon is the only choice between these two, despite its lower raw benchmark scores.

The average benchmark scores tell a similar story. The i7-3740QM has an average score of 1378, placing it at the 36th percentile of all CPUs. The Xeon D-1521 has an average score of 1367, also at the 36th percentile. The 0.8% difference in average scores is negligible in real-world terms, but it consistently favors the i7 in every individual test.

Architecture Differences

The two processors come from different generations and manufacturing processes. The Xeon D-1521 uses Broadwell architecture on a 14 nm process node, fabricated by Intel with 3,200 million transistors on a 246 mm² die. The i7-3740QM uses Ivy Bridge architecture on a 22 nm process node, also fabricated by Intel, but with 1,400 million transistors on a 160 mm² die. The Xeon's smaller process node allows for more than double the transistor count in a larger die, which is typical for server-class parts with additional features.

Cache configurations differ significantly. The Xeon D-1521 has 64 KB of L1 cache per core and 256 KB of L2 cache per core, with 1.5 MB of L3 cache per core, totaling 6 MB across four cores. The i7-3740QM also has 64 KB of L1 and 256 KB of L2 per core, but its L3 cache is 6 MB shared across all cores. While the total L3 capacity is the same, the Xeon's per-core allocation may benefit workloads that isolate threads to specific cores, while the i7's shared cache allows any core to access the full 6 MB.

Clock speeds favor the i7-3740QM substantially. The Xeon D-1521 runs at a 2.40 GHz base clock and 2.70 GHz boost clock. The i7-3740QM runs at a 2.70 GHz base clock and 3.70 GHz boost clock. The i7's 1.0 GHz higher boost clock is the primary driver of its benchmark wins, especially in single-core tests. Both processors have locked multipliers, so overclocking is not an option for either.

The Xeon D-1521 uses an Intel BGA 1667 socket, while the i7-3740QM uses Intel BGA 1224. Both are soldered, non-upgradeable packages. The Xeon offers PCIe Gen 3 with 24 lanes (CPU only), while the i7's PCIe configuration is not specified. The Xeon includes no integrated graphics, while the i7 includes Intel HD 4000. The Xeon was released on October 31, 2015, with a launch MSRP of $199, while the i7 was released on September 2, 2012, with no launch MSRP specified.

FAQ

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

A: The Core i7-3740QM wins every multi-core Cinebench test. In Cinebench R23 multi-core, it scores 4859 against the Xeon D-1521's 4728, a 2.7% advantage. The margin is identical in R15 (489 vs 476) and R20 (2040 vs 1985).

Q: Does the Xeon D-1521 have any performance advantage at all?

A: In raw benchmark scores, no. The Xeon D-1521 loses all six head-to-head tests. However, it supports ECC memory and DDR3/DDR4, features the i7-3740QM lacks, which are critical for server reliability but not reflected in Cinebench scores.

Q: Why does the i7-3740QM consistently win by such similar margins?

A: The i7-3740QM has a 3.70 GHz boost clock versus the Xeon's 2.70 GHz, a 37% higher boost frequency. Across all six tests, the delta ranges from 2.7% to 2.9%, indicating the i7's clock advantage translates into a consistent but modest performance lead in these workloads.

Q: Which processor has better single-core performance?

A: The i7-3740QM leads in all single-core tests. In Cinebench R23 single-core, it scores 686 versus the Xeon's 667, a 2.8% difference. The R15 and R20 single-core tests show similar gaps of 2.9% and 2.8%, respectively.

Q: Are these processors comparable in their target markets?

A: No. The Xeon D-1521 is a server/workstation processor with ECC memory support and PCIe Gen 3 with 24 lanes. The i7-3740QM is a mobile processor with integrated graphics and no ECC support. They share core and thread counts but serve different purposes.

Q: How do these processors compare to their nearest rivals?

A: The Xeon D-1521's average score of 1367 is nearly identical to the Intel Core i7-3820QM (1366, 0.1% delta) and the Intel Xeon E5-1410 v2 (1368, -0.1% delta). The i7-3740QM's average of 1378 matches the AMD Ryzen 3 PRO 1200 (1379, 0% delta) and is 0.2% ahead of the Intel Core i5-1030NG7 (1376).

Specification Differences

| Specification | Intel Xeon D-1521 | Intel Core i7-3740QM |

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

| Architecture | Broadwell | Ivy Bridge |

| Process Node | 14 nm | 22 nm |

| Transistors | 3,200 million | 1,400 million |

| Die Size | 246 mm² | 160 mm² |

| Base Clock | 2.40 GHz | 2.70 GHz |

| Boost Clock | 2.70 GHz | 3.70 GHz |

| L3 Cache | 1.5 MB (per core) | 6 MB (shared) |

| Socket | Intel BGA 1667 | Intel BGA 1224 |

| Memory Support | DDR3, DDR4 | Not specified |

| ECC Memory | Yes | No |

| PCIe | Gen 3, 24 Lanes (CPU only) | Not specified |

| Integrated Graphics | None | Intel HD 4000 |

| Market Segment | Server/Workstation | Mobile |

| Release Date | 2015-10-31 | 2012-09-02 |

| Launch MSRP | $199 | Not specified |

| Part Number | SR2DF | Not specified |

Head-to-Head Benchmarks

The most decisive result comes from Cinebench R23 multi-core, where the i7-3740QM scores 4859 against the Xeon D-1521's 4728. This 131-point gap represents a 2.7% advantage for the i7, and it is the largest absolute difference in any test. The i7's 3.70 GHz boost clock is the clear driver here, as both processors have identical core and thread counts.

In Cinebench R20 multi-core, the i7 scores 2040 versus the Xeon's 1985, a 55-point gap that again translates to 2.7%. The R15 multi-core test shows the same pattern: 489 for the i7, 476 for the Xeon, a 13-point gap and 2.7% delta. The consistency of these margins across three different multi-core tests suggests a fixed performance ceiling for the Xeon relative to the i7, likely due to the clock speed difference.

Single-core tests follow the same trend with slightly larger percentage gaps. In Cinebench R23 single-core, the i7 scores 686 against the Xeon's 667, a 19-point gap and 2.8% delta. The R20 single-core test shows 288 versus 280, an 8-point gap and 2.8% delta. The R15 single-core test has the largest percentage gap at 2.9%, with the i7 scoring 69 and the Xeon scoring 67.

The Xeon D-1521's performance relative to its own rivals provides context for these losses. Its average score of 1367 places it within 0.2% of the Intel Core i7-3820QM (1366) and the AMD Opteron 6376 (1370). This means the Xeon is not a weak performer in absolute terms; it simply faces a stronger opponent in the i7-3740QM, whose average score of 1378 matches the AMD Ryzen 3 PRO 1200 (1379).

The Verdict

The data shows a clear performance winner: the Core i7-3740QM outperforms the Xeon D-1521 in every benchmark test, with consistent margins of 2.7% to 2.9% across single-core and multi-core workloads. For users whose primary concern is raw Cinebench performance, the i7-3740QM is the better choice. Its 3.70 GHz boost clock provides a decisive advantage over the Xeon's 2.70 GHz, and this advantage is visible in every workload tested.

However, the Xeon D-1521 is not without its merits. It is the only one of the two that supports ECC memory, a non-negotiable feature for many server and workstation applications where data integrity is paramount. It also supports both DDR3 and DDR4 memory, offering flexibility in memory choice. The Xeon's 14 nm process node and 3,200 million transistors indicate a more modern design, even if its clock speeds are lower. For server workloads that prioritize reliability over raw speed, the Xeon D-1521's feature set outweighs its benchmark deficit.

The choice ultimately comes down to use case. Users building a server or workstation that requires ECC memory and PCIe Gen 3 with 24 lanes should select the Xeon D-1521, accepting its lower benchmark scores in exchange for these enterprise features. Users seeking maximum performance in a mobile form factor, with integrated graphics and no ECC requirement, should select the i7-3740QM, which wins all six head-to-head tests. Neither processor is a wrong choice; they simply serve different masters.