AMD Ryzen 7 7840U vs AMD Ryzen AI 5 340 Comparison

The AMD Ryzen AI 5 340 and the AMD Ryzen 7 7840U are both 28W mobile processors on AMD Socket FP8, but they represent different design generations. The recorded head-to-head data shows a clear split: the Ryzen 7 7840U wins 12 of 17 tests, while the Ryzen AI 5 340 takes 5. Despite that, the newer Zen 5 part posts a higher average benchmark score of 25981 against 25432, and a slightly better percentile standing of 78 versus 77. The results indicate two very different performance profiles rather than a simple generational upgrade.

Head-to-Head Benchmarks

The Ryzen 7 7840U dominates the head-to-head record with 12 wins out of 17 recorded tests. Its largest margin comes in Passmark data encryption, where it scores 17691 against the AI 5 340's 11470, a 35.2% advantage. Passmark integer math shows a 30.6% lead (90852 vs 63078). Random string sorting is 26% ahead (33757 vs 24970). Floating point math is 22.8% ahead (51767 vs 39967). Passmark multithread is 21.3% ahead (24782 vs 19506). Data compression is 20.4% ahead (288604 vs 229796). Extended instructions are 19.5% ahead (20432 vs 16440). Physics is 12.8% ahead (1256 vs 1095). Find prime numbers is 10% ahead (80 vs 72). Cinebench R15 single-core is 8.1% ahead (264 vs 242.6), R15 multi-core is 3.8% ahead (1990 vs 1915), and R23 multi-core is 1.5% ahead (12719 vs 12532).

The AI 5 340's five wins are concentrated in single-thread and mixed workloads. Its standout result is Cinebench R23 single-core: 1915.5 against 1677.5, a 14.2% lead. Geekbench multi-core goes to the AI 5 340 by 4.6% (9165 vs 8766), and Geekbench single-core by 3% (2140 vs 2077). Passmark single-thread is 3.3% ahead (3683 vs 3565), a result recorded twice in the database.

The pattern is instructive. The 7840U's two extra cores and higher boost clock drive its wins in math, encryption, compression, and rendering-style workloads. The AI 5 340's Zen 5 cores deliver a substantial single-core win in Cinebench R23, but that advantage does not extend to Cinebench R15 single-core, where the 7840U leads by 8.1%. The Geekbench multi-core result is the notable exception to the 7840U's throughput dominance: the AI 5 340 wins despite having fewer cores, which points to strong per-core efficiency in that benchmark.

FAQ

Q: Which processor wins more head-to-head benchmarks?

A: The AMD Ryzen 7 7840U wins 12 of the 17 recorded tests. The AMD Ryzen AI 5 340 wins the remaining 5.

Q: How large is the Ryzen AI 5 340's single-core advantage?

A: In Cinebench R23 single-core, the AI 5 340 scores 1915.5 against 1677.5, a 14.2% lead. It also leads Geekbench single-core by 3% (2140 vs 2077) and Passmark single-thread by 3.3% (3683 vs 3565).

Q: Where does the Ryzen 7 7840U show its largest lead?

A: Its biggest margin is Passmark data encryption, 17691 vs 11470, a 35.2% advantage. It also leads Passmark integer math by 30.6% and random string sorting by 26%.

Q: Do both processors share the same power and socket?

A: Yes, both are listed at 28W TDP and both use AMD Socket FP8. They are also both fabricated on TSMC's 4 nm process.

Q: Which processor has the higher average benchmark score?

A: The Ryzen AI 5 340 has an average benchmark score of 25981, compared to 25432 for the Ryzen 7 7840U. The AI 5 340 also sits at the 78th percentile versus the 77th for the 7840U.

Q: Does the Ryzen 7 7840U support ECC memory?

A: Yes, ECC memory is listed as supported on the Ryzen 7 7840U, while the Ryzen AI 5 340 does not list ECC support.

Architecture Differences

The two processors come from different AMD architectures. The Ryzen AI 5 340 is built on Zen 5 with the Krackan Point codename, part of the Ryzen AI 300 generation. The Ryzen 7 7840U is Zen 4 with the Phoenix codename, part of the 7000 series. Both are fabricated on TSMC's 4 nm process and both use AMD Socket FP8.

Core and thread counts differ. The AI 5 340 has 6 cores and 12 threads, while the 7840U has 8 cores and 16 threads. The 7840U therefore has two more physical cores and four more threads available for parallel work.

Cache hierarchies differ in both L1 and L3. The AI 5 340 has 80 KB of L1 per core and 1 MB of L2 per core, with 8 MB of L3. The 7840U has 64 KB of L1 per core and 1 MB of L2 per core, with 16 MB of shared L3. The 7840U's L3 is double the size, which helps in data-heavy workloads.

Die size and transistor counts differ. The AI 5 340 has a die size of 195 mm², while the 7840U is 178 mm². The 7840U is listed with 25,000 million transistors; the AI 5 340 has no transistor count recorded in the database.

Integrated graphics differ. The AI 5 340 carries the Radeon 840M, while the 7840U carries the Radeon 780M.

Memory support differs. The AI 5 340 supports DDR5 and LPDDR5X, while the 7840U lists DDR5 only. Both use a dual-channel memory bus with 89.6 GB/s bandwidth.

PCIe connectivity differs. The AI 5 340 has Gen 4 with 16 lanes (CPU only), while the 7840U has Gen 4 with 20 lanes (CPU only). ECC memory support is present on the 7840U but not on the AI 5 340.

Specification Differences

The following fields differ between the two processors:

| Field | AMD Ryzen AI 5 340 | AMD Ryzen 7 7840U |

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

| Cores | 6 | 8 |

| Threads | 12 | 16 |

| Base clock | 2.00 GHz | 3.30 GHz |

| Boost clock | 4.80 GHz | 5.10 GHz |

| Architecture | Zen 5 | Zen 4 |

| Codename | Krackan Point | Phoenix |

| Generation | Ryzen AI 300 (Zen 5 / Zen 5c) | Ryzen 7 (Zen 4 (Phoenix)) |

| Die size | 195 mm² | 178 mm² |

| Transistors | not recorded | 25,000 million |

| L1 cache | 80 KB per core | 64 KB per core |

| L3 cache | 8 MB | 16 MB (shared) |

| Memory support | DDR5, LPDDR5X | DDR5 |

| ECC memory | not supported | supported |

| PCIe | Gen 4, 16 lanes (CPU only) | Gen 4, 20 lanes (CPU only) |

| Integrated graphics | Radeon 840M | Radeon 780M |

| Release date | 2025-01-05 | not recorded |

| Part number | 100-000001602 | 100-000000829100-000000830100-000001131 |

| Series | not recorded | 7000 series |

Fields that are identical include TDP (28W), socket (AMD Socket FP8), process node (4 nm), foundry (TSMC), L2 cache (1 MB per core), memory bus (dual-channel), memory bandwidth (89.6 GB/s), market segment (mobile), production status (active), and multiplier lock (locked). Neither processor has a recorded launch MSRP.

Where Each One Wins

The Ryzen 7 7840U is the stronger choice for parallel, compute-heavy workloads. Its 12 wins include Passmark multithread (24782 vs 19506), integer math (90852 vs 63078), floating point math (51767 vs 39967), data compression (288604 vs 229796), data encryption (17691 vs 11470), extended instructions (20432 vs 16440), random string sorting (33757 vs 24970), physics (1256 vs 1095), and find prime numbers (80 vs 72). It also wins Cinebench R15 single-core (264 vs 242.6), R15 multi-core (1990 vs 1915), and R23 multi-core (12719 vs 12532). For rendering, encryption, compression, and math-heavy parallel tasks, the 7840U is the clear leader in the recorded data.

The Ryzen AI 5 340 wins in specific single-thread and mixed workloads. Its Cinebench R23 single-core score of 1915.5 beats the 7840U's 1677.5 by 14.2%. It also leads Geekbench multi-core (9165 vs 8766) and Geekbench single-core (2140 vs 2077), plus Passmark single-thread (3683 vs 3565). The Geekbench multi-core win is notable because the 7840U has more cores; the AI 5 340's Zen 5 efficiency appears to offset the core deficit in that test. For single-threaded responsiveness and Geekbench-style mixed workloads, the AI 5 340 is the better fit.

In the broader database context, the AI 5 340 has a slightly higher average benchmark score (25981 vs 25432) and a higher percentile (78 vs 77). Its nearest rivals include the Intel Core i7-14701TE (26013, 0.1% ahead of the AI 5 340), the AMD Ryzen 5 PRO 5655GE (25880, 0.4% behind), the AMD Ryzen 5 8640HS (26106, 0.5% ahead), and the Intel Core i7-11700K (25812, 0.7% behind). The 7840U's nearest rivals include the Intel Core i7-11700KF (25423, even), the AMD Ryzen 7 5825U (25446, 0.1% ahead), the AMD Ryzen 5 7640U (25485, 0.2% ahead), and the AMD Ryzen 5 5600X3D (25365, 0.3% behind).

The use-case split is clear. Choose the Ryzen 7 7840U for multi-threaded throughput, encryption, compression, and math-heavy parallel tasks. Choose the Ryzen AI 5 340 for single-threaded performance, Geekbench-style mixed workloads, and scenarios where the newer Zen 5 core design and LPDDR5X memory support matter.