Intel Core 5 120U vs Intel Core i7-1255U Comparison

The Intel Core 5 120U and Intel Core i7-1255U are both 10-core, 12-thread mobile processors aimed at thin-and-light laptops, but benchmark data reveals they are not interchangeable. The Core 5 120U claims a decisive 15 wins out of 17 head-to-head tests, while the Core i7-1255U takes only two, albeit in significant multi-core render workloads. The data shows a generational split: the newer Raptor Lake-based Core 5 120U dominates in single-threaded and general productivity tasks, while the older Alder Lake-based Core i7-1255U retains a lead in specific Cinebench multi-core scenarios. This analysis breaks down the exact performance deltas, architectural differences, and use-case recommendations based solely on the supplied benchmark results.

Head-to-Head Benchmarks

The most striking result is the Core i7-1255U’s victory in Cinebench R23 multi-core, where it scores 8285 against the Core 5 120U’s 6659, a 19.6% margin. This is the largest single delta in the entire comparison and indicates that the older chip can sustain higher all-core throughput in this particular render test. Similarly, in Cinebench R15 multi-core, the Core i7-1255U wins with 1387 points versus 1150.5, a 17.1% lead. These two wins suggest that the Core i7-1255U has a raw multi-threaded advantage in legacy render benchmarks, despite losing the overall war.

However, the Core 5 120U flips the script in Cinebench R20 multi-core, scoring 5349 against 4635, a 15.4% win. This inconsistency between R15, R20, and R23 multi-core scores is notable and suggests workload-specific scaling behavior rather than a simple clock-speed advantage. In single-core tests, the Core 5 120U is consistently ahead: Cinebench R15 single-core shows 245 versus 237.5 (3.2% delta), R20 single-core shows 755 versus 654 (15.4% delta), and R23 single-core shows 1756.5 versus 1647 (6.6% delta). The R20 single-core margin is particularly large, indicating a strong boost clock advantage in short, lightly-threaded bursts.

Beyond Cinebench, the Core 5 120U wins every PassMark discipline. In integer math, it scores 52280 versus 48498, a 7.8% lead. Floating-point math shows 36026 versus 32618, a 10.4% win. The largest PassMark deltas come in prime number finding, where the Core 5 120U scores 53 versus 40, a massive 32.5% advantage. Data compression and encryption also favor the Core 5 120U by 13% and 12.9%, respectively. Extended instructions (SIMD workloads) show a 13% lead for the Core 5 120U (9299 vs 8231), and random string sorting is 12.6% faster (19060 vs 16934). The overall PassMark multithread score is 15042 for the Core 5 120U versus 13234, a 13.7% win, and single-thread is 3479 versus 3192, a 9% win. Physics simulation in PassMark also favors the Core 5 120U, 937 versus 789, an 18.8% margin.

Synthetically, the Core 5 120U’s average benchmark score is 17898, placing it in the 72nd percentile of all CPUs, while the Core i7-1255U sits at 17656 in the 71st percentile. The Core 5 120U’s nearest rival is the AMD Ryzen 5 3600XT with an average score of 17891 (0% delta), while the Core i7-1255U’s closest competitor is the Intel Core i3-13100F at 17653 (0% delta). These percentile placements are nearly identical, but the head-to-head data shows the Core 5 120U is the more balanced performer across most measured tasks.

Architecture Differences

The fundamental architectural split is the node and family generation. The Core 5 120U uses the Raptor Lake architecture with the Raptor Lake-U codename, while the Core i7-1255U is based on Alder Lake with the Alder Lake-U codename. Both are fabricated on Intel’s 10 nm process node, so there is no lithography advantage. However, the Raptor Lake design is a refined version of Alder Lake, and the benchmark data reflects this in improved single-thread and PassMark performance, despite identical core and thread counts.

Both processors feature 10 cores and 12 threads, indicating a hybrid layout of performance and efficiency cores, though the exact core configuration is not specified in the data. Cache hierarchies are identical: 80 KB of L1 per core, 1.25 MB of L2 per core, and 12 MB of shared L3. This means the performance differences cannot be attributed to cache capacity. The boost clock differs, with the Core 5 120U hitting 5.00 GHz versus the Core i7-1255U’s 4.70 GHz, which explains the Core 5 120U’s dominance in single-threaded and burst workloads. The base clock is listed oddly: the Core 5 120U shows 1.40 GHz while the Core i7-1255U shows 1700.00 (likely a formatting artifact, but the data stands as 1.40 vs 1700.00).

Integrated graphics are a clear differentiator: the Core 5 120U comes with Iris Xe Graphics 80EU, while the Core i7-1255U has Iris Xe 96EU. The 96EU configuration on the Core i7-1255U is a larger GPU, but no graphics benchmarks are provided, so the impact on gaming or media tasks is qualitative. PCIe lanes also differ: the Core 5 120U supports Gen 4 with 8 lanes (CPU only), while the Core i7-1255U supports Gen 4 with 20 lanes (CPU only). This gives the Core i7-1255U a significant advantage in available bandwidth for discrete GPUs or high-speed storage. Both support DDR4 and DDR5 memory in dual-channel mode, with no ECC support. The Core 5 120U was released on 2024-01-07, while the Core i7-1255U launched earlier on 2022-02-22, making the Core 5 120U the newer part.

Where Each One Wins

The Core 5 120U is the clear winner for general-purpose productivity and single-threaded responsiveness. Its 9% lead in PassMark single-thread, 15.4% lead in Cinebench R20 single-core, and 6.6% lead in R23 single-core make it the better choice for office applications, web browsing, and software compilation that relies on burst performance. The data also shows it excels in encryption (12.9% faster), compression (13% faster), and integer math (7.8% faster), which are common in database work, file archiving, and financial modeling. For developers, the extended instructions benchmark (13% faster) indicates better SIMD throughput for scientific or media processing code. The 32.5% win in prime number finding suggests a strong advantage in certain algorithmic workloads or cryptography-related tasks, though this is a niche metric.

The Core i7-1255U wins specifically in Cinebench R23 multi-core (19.6% ahead) and R15 multi-core (17.1% ahead). This indicates that for sustained all-core render workloads in these specific benchmark versions, the Core i7-1255U is the superior choice. If a user’s primary application is video rendering using legacy Cinebench R15 or current R23, the Core i7-1255U will deliver better frame times. However, this advantage does not carry over to R20 multi-core, where the Core 5 120U wins by 15.4%, suggesting the Core i7-1255U’s lead is benchmark-version-specific rather than a general multi-threaded strength. The Core i7-1255U also has the PCIe Gen 4 20-lane advantage, which is not benchmarked but could provide faster connectivity for external GPUs or NVMe RAID configurations.

For most users, the Core 5 120U is the better all-rounder. It wins the PassMark multithread test (13.7% ahead), physics simulation (18.8% ahead), and all single-thread tests. The only scenario where the Core i7-1255U is unequivocally recommended is for workloads that heavily depend on Cinebench R23-style rendering, where its 19.6% lead is substantial. Otherwise, the Core 5 120U’s superior single-core and PassMark suite performance, coupled with its newer release date, make it the more versatile mobile processor.

Specification Differences

The two CPUs share many specs but differ in key fields. The Core 5 120U uses Raptor Lake architecture, while the Core i7-1255U uses Alder Lake. The codenames are Raptor Lake-U and Alder Lake-U, respectively. The boost clock favors the Core 5 120U at 5.00 GHz versus 4.70 GHz for the Core i7-1255U. The base clock is listed as 1.40 GHz for the Core 5 120U and 1700.00 for the Core i7-1255U (the data is inconsistent, but the values are as provided). The integrated graphics differ: Iris Xe Graphics 80EU for the Core 5 120U versus Iris Xe 96EU for the Core i7-1255U. PCIe lanes are different: Gen 4 with 8 lanes (CPU only) for the Core 5 120U versus Gen 4 with 20 lanes (CPU only) for the Core i7-1255U. The release dates are 2024-01-07 for the Core 5 120U and 2022-02-22 for the Core i7-1255U. The part numbers are SRM7P for the Core 5 120U and SRLFP for the Core i7-1255U. Both have the same core count (10), thread count (12), TDP (15), socket (Intel BGA 1744), process node (10 nm), L1 cache (80 KB per core), L2 cache (1.25 MB per core), L3 cache (12 MB shared), memory support (DDR4, DDR5), memory bus (Dual-channel), ECC support (false), multiplier unlocked (false), and market segment (Mobile). Both are Active in production status.

FAQ

Q: Which processor has a higher boost clock?

A: The Intel Core 5 120U has a boost clock of 5.00 GHz, while the Intel Core i7-1255U has a boost clock of 4.70 GHz.

Q: How much faster is the Core 5 120U in single-threaded PassMark performance?

A: The Core 5 120U scores 3479 in PassMark single-thread, while the Core i7-1255U scores 3192, representing a 9% lead for the Core 5 120U.

Q: In which benchmark does the Core i7-1255U have its largest win over the Core 5 120U?

A: The Core i7-1255U wins Cinebench R23 multi-core by 19.6%, scoring 8285 versus the Core 5 120U’s 6659.

Q: Do both processors have the same cache configuration?

A: Yes, both have 80 KB of L1 per core, 1.25 MB of L2 per core, and 12 MB of shared L3 cache.

Q: Which processor has a newer release date?

A: The Intel Core 5 120U was released on 2024-01-07, while the Intel Core i7-1255U was released on 2022-02-22.

Q: What is the difference in integrated graphics between the two?

A: The Core 5 120U features Iris Xe Graphics 80EU, while the Core i7-1255U features Iris Xe 96EU, with the latter having more execution units.