Intel Core 2 Extreme QX9775 vs Intel Core i7-5550U Comparison

Head-to-Head Benchmarks

The benchmark data presents a striking anomaly: across every single Cinebench test, the Intel Core i7-5550U and the Intel Core 2 Extreme QX9775 achieve identical scores. In Cinebench R15 multicore, both processors post 238 points. The R20 multicore test shows both at 992, and the R20 singlecore test has both at 139. Moving to R23, the multicore result is 2363 for each, while the singlecore test yields 333 for both. The deltaPct is 0% across all five comparisons.

This is not a case of one chip edging out the other by a small margin. The scores are perfectly equal, which raises immediate questions about how two processors from vastly different eras, with different core counts and power envelopes, can produce identical rendering performance. The head-to-head table marks the i7-5550U as the winner in all five tests, but this designation is purely nominal — a tiebreaker convention rather than a demonstration of superiority. The winsA count of 5 against winsB of 0 reflects this scoring rule, not actual performance dominance.

What does this mean in practical terms? The average benchmark score for both CPUs is 813, placing each at the 22nd percentile of all CPUs in the database. Their nearest rivals provide context: the Intel Xeon X3440 scores 815 (a -0.2% delta), the Intel Core i5-L16G7 scores 816 (-0.4%), and the AMD A10-6800K scores 809 (+0.5%). The i7-5550U and QX9775 sit squarely in the middle of this cluster, effectively indistinguishable in aggregate performance.

The identical scores suggest that whatever workload Cinebench represents — typically multi-threaded rendering — the two chips are perfectly matched. The i7-5550U accomplishes this with 2 cores and 4 threads, while the QX9775 uses 4 cores and 4 threads. This implies that the newer architecture of the i7-5550U compensates for having half the physical cores. The data does not show any single-core advantage for either part, which is unusual given the generational gap between Broadwell and Yorkfield.

Architecture Differences

The architectural chasm between these two processors is substantial, yet the benchmark results show no performance gap. The i7-5550U is built on a 14 nm process node, while the QX9775 uses a 45 nm node. This translates into a dramatic difference in transistor density: the i7-5550U packs 1,900 million transistors onto a 133 mm² die, whereas the QX9775 has 820 million transistors spread across two 107 mm² dies. The newer chip crams more than twice the transistors into a smaller area.

Core configuration tells a story of different design philosophies. The i7-5550U has 2 cores and 4 threads, enabling simultaneous multithreading. The QX9775 has 4 physical cores and 4 threads, with no hyper-threading. Despite having twice the core count, the older processor cannot outperform the dual-core part. The i7-5550U's base clock is 2000 MHz with a boost clock of 3.00 GHz. The QX9775 runs at a fixed 3.20 GHz with no boost capability.

Cache hierarchies also diverge. Both share 64 KB of L1 per core and 256 KB of L2 per core on the i7-5550U versus 6 MB of L2 per die on the QX9775. The i7-5550U has 4 MB of shared L3 cache, while the QX9775 has no L3 at all. This difference likely explains how the newer chip keeps pace despite lower clock speeds — the larger, smarter cache hierarchy compensates for the raw frequency deficit.

Power consumption is where the two parts diverge most dramatically. The i7-5550U has a TDP of 15 watts, while the QX9775 draws 150 watts — a tenfold difference. This positions the i7-5550U for mobile use with integrated Intel HD 6000 graphics, while the QX9775 is a desktop part with no integrated graphics. The QX9775 does support ECC memory and has an unlocked multiplier, features absent on the i7-5550U. Memory support differs as well: DDR3 dual-channel with 29.9 GB/s bandwidth on the newer chip, versus DDR2 depending on the motherboard for the older one.

FAQ

Q: Why do two CPUs with different core counts score identically in every benchmark?

A: The data shows both processors achieving exactly 238 in Cinebench R15 multicore, 992 in R20 multicore, and 2363 in R23 multicore. The i7-5550U's architectural advantages — a 14 nm process, 1,900 million transistors, and 4 MB of shared L3 cache — appear to fully offset the QX9775's advantage of having 4 physical cores versus 2. The newer chip also benefits from a boost clock reaching 3.00 GHz, close to the QX9775's fixed 3.20 GHz.

Q: Which processor is more power-efficient?

A: The i7-5550U has a TDP of 15 watts, while the QX9775 has a TDP of 150 watts. This means the i7-5550U delivers the same benchmark performance at one-tenth the power draw, making it dramatically more efficient for sustained workloads.

Q: Does the QX9775's higher clock speed give it any advantage?

A: The QX9775 runs at 3.20 GHz base with no boost, while the i7-5550U runs at 2000 MHz base and boosts to 3.00 GHz. Despite the QX9775's higher sustained clock, benchmark results show no performance advantage — both score 139 in R20 singlecore and 333 in R23 singlecore.

Q: Can the QX9775 be overclocked?

A: Yes, the QX9775 has an unlocked multiplier, indicated in its specifications. The i7-5550U does not have an unlocked multiplier. However, the benchmark data only reflects stock performance, not overclocked results.

Q: What market segments were these processors designed for?

A: The i7-5550U is a mobile processor released on 2015-02-28, while the QX9775 is a desktop part released on 2008-03-23. The i7-5550U includes integrated Intel HD 6000 graphics, whereas the QX9775 has no integrated graphics.

Q: How do these CPUs compare to their nearest rivals in the database?

A: Both sit at the 22nd percentile of all CPUs with an average score of 813. The Intel Xeon X3440 scores 815 (-0.2%), the Intel Core i5-L16G7 scores 816 (-0.4%), and the AMD A10-6800K scores 809 (+0.5%). All four chips are within a fraction of a percent of each other.

Specification Differences

| Specification | Intel Core i7-5550U | Intel Core 2 Extreme QX9775 |

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

| Cores | 2 | 4 |

| Threads | 4 | 4 |

| Base Clock | 2000.00 MHz | 3.20 GHz |

| Boost Clock | 3.00 GHz | None |

| TDP | 15 W | 150 W |

| Socket | Intel BGA 1168 | Intel Socket 771 |

| Architecture | Broadwell | Core 2 |

| Codename | Broadwell-U | Yorkfield |

| Process Node | 14 nm | 45 nm |

| Transistors | 1,900 million | 820 million |

| Die Size | 133 mm² | 2x 107 mm² |

| L2 Cache | 256 KB (per core) | 6 MB (per die) |

| L3 Cache | 4 MB (shared) | None |

| Memory Support | DDR3 | DDR2 (depends on motherboard) |

| Memory Bus | Dual-channel | Not specified |

| Memory Bandwidth | 29.9 GB/s | Not specified |

| ECC Memory | No | Yes |

| PCIe | Gen 2, 12 Lanes (CPU only) | Gen 1 |

| Integrated Graphics | Intel HD 6000 | None |

| Market Segment | Mobile | Desktop |

| Release Date | 2015-02-28 | 2008-03-23 |

| Launch MSRP | $426 | $1499 |

| Multiplier Unlocked | No | Yes |

| Part Number | SR26A | SLANYEU80574XL088N |

The Verdict

The data presents a genuine paradox. The Intel Core i7-5550U, a 2-core mobile chip from 2015, matches the Intel Core 2 Extreme QX9775, a 4-core desktop flagship from 2008, in every measured benchmark. Both achieve identical scores across Cinebench R15, R20, and R23 in both single-core and multi-core tests. The average benchmark score of 813 for each reinforces this parity.

The i7-5550U achieves this with a 15-watt TDP versus 150 watts for the QX9775. It uses a 14 nm process against 45 nm, packs 1,900 million transistors versus 820 million, and includes 4 MB of shared L3 cache where the QX9775 has none. The newer chip also brings integrated graphics, dual-channel DDR3 support with 29.9 GB/s bandwidth, and PCIe Gen 2 connectivity.

The QX9775 counters with an unlocked multiplier for overclocking, ECC memory support, and a higher base clock of 3.20 GHz. It was launched at a significantly higher MSRP of $1499 versus $426, though both are now end-of-life products.

For most users, the i7-5550U is the more compelling choice based on data alone. It delivers identical performance at a fraction of the power draw, in a smaller mobile form factor, with integrated graphics and modern memory support. The QX9775 only makes sense for scenarios requiring ECC memory or overclocking — features the benchmark data does not measure.

Where Each One Wins

The i7-5550U wins in every scenario the benchmark data can evaluate. It matches the QX9775 in raw Cinebench performance while offering superior power efficiency, modern connectivity, and integrated graphics. For mobile computing, the 15-watt TDP and BGA 1168 socket make it the obvious choice. The 14 nm process and 1,900 million transistors indicate a design optimized for performance-per-watt, a metric where the QX9775 cannot compete.

The QX9775 retains theoretical advantages in specific non-benchmark scenarios. Its unlocked multiplier allows overclocking, potentially pushing performance beyond stock levels — though the data does not quantify this. ECC memory support makes it viable for error-sensitive workloads. The 4 physical cores without hyper-threading could theoretically benefit workloads that scale with raw core count rather than thread count, though Cinebench results show no such advantage.

The desktop Socket 771 platform offers upgrade paths and expansion options that the BGA 1168 mobile socket cannot match. The QX9775's higher base clock of 3.20 GHz, when combined with overclocking, might overcome the architectural deficits in latency-sensitive tasks. However, the benchmark data shows no evidence of this advantage in tested workloads.

Ultimately, the i7-5550U wins on efficiency, modernity, and practical usability. The QX9775 wins only on niche features like ECC support and overclocking headroom. For any workload represented by the Cinebench suite, the choice is irrelevant — both deliver identical numbers. The deciding factors lie outside the benchmarks, in power consumption, platform compatibility, and feature sets.