AMD Ryzen 7 5825U vs AMD Ryzen 7 7840U Comparison

AMD Ryzen 7 5825U and AMD Ryzen 7 7840U are both 8-core, 16-thread mobile processors, but they represent two distinct generations of AMD's mobile lineup. The 5825U is a Zen 3 part from the 5000 series, while the 7840U is a Zen 4 part from the 7000 series. Benchmark data shows the 7840U wins every single head-to-head test, with deltas ranging from 11.7% to 40% depending on the workload. The 5825U holds a slim 0.1% edge in average benchmark score across all CPUs, but that is effectively a statistical tie. This analysis breaks down the architectural differences, workload-specific wins, and specification changes that separate these two mobile CPUs.

FAQ

Q: Which CPU has the higher boost clock?

A: The AMD Ryzen 7 7840U boosts to 5.10 GHz, while the AMD Ryzen 7 5825U tops out at 4.50 GHz.

Q: What is the process node difference between the two?

A: The 5825U is built on TSMC's 7 nm process with 10,700 million transistors, while the 7840U uses TSMC's 4 nm process with 25,000 million transistors.

Q: Do both CPUs support ECC memory?

A: Yes, both the Ryzen 7 5825U and the Ryzen 7 7840U list ECC memory support as a feature.

Q: How much faster is the 7840U in Cinebench R23 multi-core?

A: The 7840U scores 12,719 versus the 5825U's 10,152, which is a 20.2% advantage for the newer chip.

Q: Which CPU has the larger L2 cache per core?

A: The 7840U has 1 MB of L2 cache per core, double the 512 KB per core found on the 5825U.

Q: Are both CPUs unlocked for overclocking?

A: No, neither CPU has an unlocked multiplier; both are locked parts.

Architecture Differences

The architectural gap here is significant because it spans two generations. The Ryzen 7 5825U is based on Zen 3 architecture under the "Barcelo" codename, while the Ryzen 7 7840U uses Zen 4 architecture with the "Phoenix" codename. This is not a minor refresh; it is a full microarchitecture change. The 5825U's generation is listed as "Ryzen 7 (Zen 3 (Cezanne))" and the 7840U is "Ryzen 7 (Zen 4 (Phoenix))", confirming they are built around different core designs.

The process node is a major dividing line. The 5825U uses a 7 nm process from TSMC with 10,700 million transistors on a 180 mm² die. The 7840U moves to a 4 nm process from the same foundry, packing 25,000 million transistors on a slightly smaller 178 mm² die. That is more than double the transistor count on a smaller die, which explains the large performance per watt improvements seen in the benchmarks. The 7840U also has double the L2 cache per core: 1 MB versus 512 KB on the 5825U. Both share the same 16 MB of L3 cache and 64 KB of L1 cache per core.

Memory architecture differs substantially. The 5825U supports DDR4 memory with dual-channel configuration and a maximum bandwidth of 51.2 GB/s. The 7840U moves to DDR5 memory, also dual-channel, but with a much higher 89.6 GB/s of bandwidth. PCIe support also improves: the 5825U offers Gen 3 with 16 lanes (CPU only), while the 7840U provides Gen 4 with 20 lanes (CPU only). Both CPUs feature integrated graphics, but they are different models: the 5825U has Radeon Vega 8, and the 7840U has Radeon 780M. The 7840U also has a higher TDP of 28 watts versus 15 watts for the 5825U, which is worth noting for thermal design.

Where Each One Wins

The data is unambiguous: the Ryzen 7 7840U wins in every category tested. Out of 17 head-to-head benchmark comparisons, the 7840U takes all 17 wins. The 5825U does not secure a single victory. That said, the 5825U does have its own niche. Its 15-watt TDP is substantially lower than the 7840U's 28-watt TDP, making it a better fit for ultra-thin, fanless, or passively cooled designs where power draw is the primary constraint. The 5825U also supports DDR4 memory, which could be an advantage in systems reusing existing memory modules or in regions where DDR5 is harder to source.

For workloads, the 7840U's wins are broad and consistent. In single-threaded tests, it leads by 12.1% to 22.1%, depending on the benchmark. In multi-threaded workloads, the gap widens further, with the 7840U often leading by 20% or more. The 7840U is the clear choice for anyone who needs maximum compute performance in a mobile form factor. The 5825U is the choice for efficiency-focused designs where the lower TDP is more important than raw speed.

Specification Differences

The two CPUs differ on nearly every major specification. Core count is the same at 8 cores and 16 threads, but base and boost clocks differ: the 5825U runs at 2.00 GHz base and 4.50 GHz boost, while the 7840U runs at 3.30 GHz base and 5.10 GHz boost. TDP is 15 watts for the 5825U versus 28 watts for the 7840U. The socket changes from AMD Socket FP6 on the 5825U to AMD Socket FP8 on the 7840U, meaning they are not drop-in compatible.

Cache configuration differs in L2: the 5825U has 512 KB per core, the 7840U has 1 MB per core. L1 and L3 are identical at 64 KB per core and 16 MB shared, respectively. Memory support moves from DDR4 to DDR5, with memory bandwidth increasing from 51.2 GB/s to 89.6 GB/s. PCIe lanes improve from Gen 3 with 16 lanes to Gen 4 with 20 lanes. Integrated graphics change from Radeon Vega 8 to Radeon 780M. The process node shrinks from 7 nm to 4 nm, with transistor count jumping from 10,700 million to 25,000 million. Die size is nearly identical at 180 mm² versus 178 mm². Both support ECC memory, both are locked, and neither has a launch MSRP listed.

Head-to-Head Benchmarks

The 7840U's dominance is most pronounced in compute-heavy tasks. In PassMark's find prime numbers test, the 7840U scores 80 versus the 5825U's 48, a 40% advantage. That is the largest single delta in the dataset. PassMark physics shows a similar story: 1,256 for the 7840U versus 774 for the 5825U, a 38.4% gap. These are heavily parallel workloads that scale with core efficiency and memory bandwidth, and the newer architecture clearly benefits.

In Cinebench R23 multi-core, the 7840U scores 12,719 versus 10,152 for the 5825U, a 20.2% difference. Single-core in the same test shows a 13.4% gap, with 1,677.5 versus 1,452. Cinebench R15 shows smaller but still significant gaps: 11.7% in multi-core and 12.1% in single-core. Geekbench results are similar, with the 7840U leading by 16.9% in multi-core and 22.1% in single-core.

PassMark's suite shows consistent double-digit wins for the 7840U across the board. Data compression favors the 7840U by 23.1% (288,604 versus 221,938). Data encryption is 20.4% faster (17,691 versus 14,088). Extended instructions show a 29.6% gap (20,432 versus 14,394). Floating point math is 25.7% faster (51,767 versus 38,482), and integer math is 20.1% faster (90,852 versus 72,577). The PassMark multi-thread score shows a 26.8% difference (24,782 versus 18,131), and single-thread shows 14.4% (3,565 versus 3,053). Random string sorting is 30.3% faster on the 7840U (33,757 versus 23,539).

The Verdict

The data points to a clear winner for performance: the AMD Ryzen 7 7840U is faster in every single benchmark recorded. It wins all 17 head-to-head tests, with deltas ranging from 11.7% to 40%. The average benchmark scores are nearly identical — 25,446 for the 5825U and 25,432 for the 7840U — but that average masks the fact that the 7840U wins every individual test. The 5825U is not a bad processor; it sits at the 78th percentile versus the 7840U's 77th, but the percentile ranking is based on the aggregate average, not the head-to-head results.

The choice comes down to platform priorities. The 7840U is the right pick if you want the fastest mobile performance available in this comparison. Its higher boost clock, larger L2 cache, DDR5 support, Gen 4 PCIe, and double the transistor count deliver measurable gains in every workload. The 5825U is the right pick if power efficiency is the absolute priority. Its 15-watt TDP is nearly half of the 7840U's 28-watt TDP, which matters for battery life and thermal headroom in thin-and-light designs. The 5825U also supports DDR4, which may be preferable in cost-sensitive or legacy-memory scenarios. But for raw compute, the 7840U is the definitive winner.