AMD Ryzen 9 7945HX3D vs AMD Ryzen 9 9900X Comparison

The AMD Ryzen 9 7945HX3D and the AMD Ryzen 9 9900X sit in the 92nd percentile of all CPUs in the database, yet they arrive there by very different routes. One is a 16-core mobile monster with 3D V-Cache; the other is a 12-core desktop part built on a newer Zen 5 architecture. Their average benchmark scores land within roughly four percent of each other, 59641 versus 57498, but the head-to-head record splits 13 wins to 10 in favor of the 9900X, and the pattern behind those wins tells a clearer story than the tally alone. What emerges is a divide between lightly threaded responsiveness and heavily threaded throughput, with a few surprising outliers in the physics and encryption tests that raise interesting questions.

Head-to-Head Benchmarks

The single-threaded results are the most one-sided story in the dataset. The Ryzen 9 9900X takes every lightly threaded test: 3DMark single thread at 1286 versus 1071 (a 16.7 percent gap in its favor), 3DMark 2 threads at 2519 versus 2095, 4 threads at 4886 versus 3937 (19.4 percent), and 8 threads at 9114 versus 7330 (19.6 percent). The same pattern holds in Cinebench R15 single core, 353 against 311 (11.9 percent), Cinebench R23 single core, 2253 against 1935 (14.1 percent), Geekbench single core, 3010 against 2769 (8 percent), and Passmark single thread, 4672 against 4050 (13.3 percent). That is a consistent, architecture-driven advantage for the Zen 5 desktop chip whenever the workload is narrow.

Flip to heavily threaded throughput and the 7945HX3D answers. Its 16 cores and 32 threads carry Cinebench R15 multi-core at 5600 versus 5008, an 11.8 percent win, and Cinebench R23 multi-core at 32782 versus 32172, a 1.9 percent edge. Passmark multithread goes to the mobile part 57476 to 54643, a 5.2 percent margin. The core-count advantage clearly translates into real multi-core performance, even though the 9900X still wins 3DMark max threads at 13929 versus 12936 (7.1 percent) and dominates Geekbench multi-core 22174 to 16758, a 24.4 percent gap that stands out as the dataset's largest single discrepancy. Why Geekbench rewards the 9900X so heavily in multi-core while Cinebench and Passmark lean the other way is a fair question; the answer likely lies in how each suite scales with per-core throughput versus raw thread count, but the data itself shows the divergence plainly.

The Passmark subtests mostly favor the 7945HX3D, and some by wide margins. Physics is the standout: 4321 versus 3381, a 27.8 percent win, the largest advantage for either CPU in the entire dataset. Data encryption goes to the mobile chip 42367 versus 33421 (26.8 percent), random string sorting 83919 versus 72013 (16.5 percent), integer math 201217 versus 181056 (11.1 percent), data compression 699988 versus 683579 (2.4 percent), prime finding 446 versus 436 (2.3 percent), and floating point math 121619 versus 120083 (1.3 percent). The 9900X's only Passmark subtest win is extended instructions, 55243 versus 52310 (5.3 percent). Curiously, 3DMark 16 threads is nearly a dead heat, 12552 versus 12459, a mere 0.7 percent apart, suggesting that once a workload saturates sixteen threads the two are effectively matched in that suite.

Architecture Differences

These are fundamentally different designs serving different markets. The 7945HX3D is a mobile processor from the 7000 series, codenamed Dragon Range, built on Zen 4 architecture at TSMC on a 5 nm process, with 17,840 million transistors across a 2x 71 mm² die configuration and the FL1 socket. The 9900X is a desktop processor from the 9000 series, codenamed Granite Ridge, built on Zen 5 at TSMC on a 4 nm process, with 16,630 million transistors across 2x 70.6 mm² dies and the AM5 socket. The newer, denser node is part of why the desktop part clocks higher: 4.40 GHz base and 5.60 GHz boost, against 2.30 GHz base and 5.40 GHz boost for the mobile chip.

The core and cache configurations diverge sharply. The 7945HX3D has 16 cores and 32 threads with 64 KB of L1 per core, 1 MB of L2 per core, and 128 MB of shared L3, which includes a 64 MB 3D V-Cache slice. The 9900X has 12 cores and 24 threads with a larger 80 KB of L1 per core, the same 1 MB of L2 per core, but only 64 MB of L3 and no V-Cache. That cache difference is the mobile chip's signature feature and plausibly explains its strength in cache-sensitive workloads like the Passmark physics and encryption tests.

Platform details also differ. The 7945HX3D runs DDR5 over a dual-channel bus at 83.2 GB/s of bandwidth, offers 28 Gen 5 PCIe lanes from the CPU, includes Radeon 610M integrated graphics, and carries a 55 watt TDP. The 9900X also supports DDR5 dual-channel but with higher bandwidth at 89.6 GB/s, provides 24 Gen 5 CPU lanes, ships with Radeon Graphics integrated, and carries a 120 watt TDP. Both support ECC memory and both have unlocked multipliers, so neither is locked away from overclockers. Both remain in active production. The 9900X launched later, in August 2024, following the 7945HX3D's July 2023 release, and carries a launch MSRP of $499.

Where Each One Wins

The data paints an unusually clean split. The 9900X owns latency-sensitive and lightly threaded workloads: every single-thread and low-thread-count test in the dataset, plus Geekbench multi-core by 24.4 percent and 3DMark max threads by 7.1 percent. Users whose software depends on snappy per-thread performance, or on benchmarks that reward per-core throughput, will see the Zen 5 part pull ahead consistently, often by double-digit margins in the 2-thread through 8-thread range.

The 7945HX3D owns sustained, cache-hungry, and genuinely parallel workloads. Its 27.8 percent physics win and 26.8 percent encryption win in Passmark are the kinds of margins that reshape a comparison, and its integer math, sorting, compression, and Cinebench multi-core wins confirm the pattern. With 16 physical cores and double the L3 cache through V-Cache, it is the pick for rendering-style throughput and memory-local compute. Interestingly, its Passmark multithread win (5.2 percent) coexists with a Geekbench multithread loss (24.4 percent), a reminder that "multi-core performance" is not one number but several, and buyers should match the benchmark to their actual software.

FAQ

Q: Which CPU is faster in single-threaded work?

A: The Ryzen 9 9900X, decisively. It wins every single-thread test: Geekbench 3010 versus 2769 (8 percent), Cinebench R23 2253 versus 1935 (14.1 percent), 3DMark 1286 versus 1071 (16.7 percent), and Passmark 4672 versus 4050 (13.3 percent).

Q: Which one wins in multi-core benchmarks?

A: It depends on the suite. The 7945HX3D wins Cinebench R15 multi-core by 11.8 percent, Cinebench R23 multi-core by 1.9 percent, and Passmark multithread by 5.2 percent, while the 9900X wins Geekbench multi-core by 24.4 percent and 3DMark max threads by 7.1 percent.

Q: What accounts for the 7945HX3D's huge Passmark physics win?

A: The recorded data shows a 27.8 percent margin (4321 versus 3381). The mobile chip's 128 MB of shared L3, including a 64 MB 3D V-Cache slice, and its 16 cores are the distinguishing hardware features that plausibly explain cache-sensitive throughput advantages.

Q: Do these CPUs support the same memory?

A: Both support ECC-capable DDR5 over a dual-channel bus, but bandwidth differs: 89.6 GB/s on the 9900X versus 83.2 GB/s on the 7945HX3D.

Q: Can both be overclocked?

A: Yes, both the 7945HX3D and the 9900X have unlocked multipliers.

Q: How do they compare against other CPUs in the database?

A: Both sit in the 92nd percentile versus all CPUs. The 7945HX3D's average score of 59641 sits within about one percent of rivals like the Intel Core i9-14900F (60008) and Ryzen 9 7945HX (60099), while the 9900X's 57498 is similarly close to the AMD EPYC 9015 (57555) and Intel Core i9-14900 (58115).

The Verdict

The data supports a simple rule. If the workload is lightly threaded or measured by Geekbench, the 9900X is the stronger performer, winning 13 of 23 head-to-head tests including every single-thread contest, and it does so with a newer architecture, a higher boost clock, and higher memory bandwidth. If the workload saturates threads or leans on cache, the 7945HX3D is the pick, winning 10 tests including the three largest margins anywhere in the dataset: physics (27.8 percent), encryption (26.8 percent), and Geekbench multi-core aside, Cinebench R15 multi-core (11.8 percent). Both deliver 92nd-percentile performance, so neither is a compromise choice; the deciding factor is simply whether the software in question rewards per-core speed or parallel, cache-hungry throughput.

Specification Differences

• Market segment: Mobile (7945HX3D) versus Desktop (9900X)
• Socket: AMD Socket FL1 versus AMD Socket AM5
• Architecture: Zen 4 (Dragon Range) versus Zen 5 (Granite Ridge)
• Series: 7000 series versus 9000 series
• Cores/threads: 16 cores, 32 threads versus 12 cores, 24 threads
• Base clock: 2.30 GHz versus 4.40 GHz
• Boost clock: 5.40 GHz versus 5.60 GHz
• TDP: 55 W versus 120 W
• Process node: 5 nm versus 4 nm (both TSMC)
• Transistors: 17,840 million versus 16,630 million
• Die size: 2x 71 mm² versus 2x 70.6 mm²
• L1 cache: 64 KB per core versus 80 KB per core
• L3 cache: 128 MB shared with a 64 MB 3D V-Cache slice versus 64 MB, no V-Cache
• Memory bandwidth: 83.2 GB/s versus 89.6 GB/s (both DDR5 dual-channel with ECC)
• PCIe: Gen 5, 28 CPU lanes versus Gen 5, 24 CPU lanes
• Integrated graphics: Radeon 610M versus Radeon Graphics
• Release date: July 2023 versus August 2024
• Launch MSRP: not recorded for the 7945HX3D; $499 for the 9900X
• Part number: 100-000001086 versus 100-000000662