AMD Ryzen 9 9900X3D vs Intel Core Ultra X9 378H Comparison

The AMD Ryzen 9 9900X3D and the Intel Core Ultra X9 378H target entirely different platforms, and the benchmark data reflects that divide. The Ryzen 9 9900X3D is a 12-core desktop processor built for maximum throughput, while the Core Ultra X9 378H is a 16-core mobile part designed for efficiency. Across every recorded head-to-head benchmark, the AMD chip delivers a higher score, with margins ranging from a modest 4.3% in single-thread tests to a decisive 94.1% in integer math. The data shows a clear performance hierarchy, but the selection between these two ultimately depends on the intended use case, desktop versus mobile.

FAQ

Q: Which processor has more cores and threads?

A: The Intel Core Ultra X9 378H has 16 cores but only 16 threads, meaning it does not support simultaneous multithreading. The AMD Ryzen 9 9900X3D has 12 cores and 24 threads, giving it a higher thread count despite having fewer physical cores.

Q: How large is the cache difference between the two?

A: The AMD Ryzen 9 9900X3D features a massive 128 MB of L3 cache, while the Intel Core Ultra X9 378H has 18 MB of shared L3 cache. The AMD part also has 80 KB of L1 cache per core and 1 MB of L2 cache per core, compared to Intel's 192 KB of L1 per core and 2.5 MB of L2 per core.

Q: What memory types do these processors support?

A: The AMD Ryzen 9 9900X3D supports DDR5 memory with a dual-channel bus and a recorded bandwidth of 89.6 GB/s. The Intel Core Ultra X9 378H supports LPDDR5X memory, also with a dual-channel bus, but with a higher recorded bandwidth of 153.6 GB/s.

Q: Which processor has a higher boost clock?

A: The AMD Ryzen 9 9900X3D has a boost clock of 5.50 GHz, which is higher than the Intel Core Ultra X9 378H's boost clock of 5.00 GHz.

Q: Are both processors unlocked for overclocking?

A: The AMD Ryzen 9 9900X3D has its multiplier unlocked. The Intel Core Ultra X9 378H has its multiplier locked.

Q: Which processor shows a higher average benchmark score?

A: The AMD Ryzen 9 9900X3D has an average benchmark score of 54762, while the Intel Core Ultra X9 378H has an average benchmark score of 47468. The AMD part also holds a higher percentile rank at 91 versus Intel's 89.

Where Each One Wins

The head-to-head benchmark results are one-sided: the AMD Ryzen 9 9900X3D wins all 17 recorded comparisons. The Intel Core Ultra X9 378H does not secure a single victory in any of the tested workloads. That said, the nature of the wins varies significantly by workload type.

The AMD part's largest advantages come in compute-heavy integer and compression tasks. It leads by 94.1% in PassMark integer math, 77.2% in data compression, and 77% in extended instructions. These are workloads that scale with raw core throughput and large caches. The Ryzen 9 9900X3D also posts a 61% lead in random string sorting and a 56.9% lead in the PassMark physics test. For multi-threaded rendering, the Cinebench results are consistent, with the AMD chip holding a 46.6% advantage across R15, R20, and R23 multicore tests.

The Intel part's closest margins are in single-thread and floating-point workloads. The gap narrows to 4.3% in PassMark single-thread performance and 4.5% in floating-point math. These results indicate that the mobile chip is competitive in lightly threaded scalar work, even if it cannot match the desktop processor's overall output. The data suggests that if any workload favors the Intel part, it would be in efficiency-sensitive mobile scenarios, though no such benchmark win is recorded.

Architecture Differences

The architectural split between these two processors is fundamental. The AMD Ryzen 9 9900X3D is built on the Zen 5 architecture with the Granite Ridge codename, manufactured on a 4 nm process at TSMC. It uses a chiplet design with a die size of 2x 70.6 mm² and contains 16,630 million transistors. The Intel Core Ultra X9 378H uses the Panther Lake codename from the Core Ultra Series 3, built on a 3 nm process at Intel's own foundry. Intel's transistor count and die size are not recorded in the database.

Cache architecture also diverges sharply. AMD's design features a large 128 MB L3 cache, which is the defining characteristic of the X3D line. Intel's part uses a smaller 18 MB shared L3 cache but compensates with larger per-core L1 and L2 caches: 192 KB and 2.5 MB per core, respectively. The AMD part has 80 KB of L1 and 1 MB of L2 per core. These differences directly explain the benchmark results: AMD's larger L3 cache benefits workloads with large working sets, while Intel's larger per-core caches help with moderate thread counts.

The platforms are incompatible. The AMD processor uses Socket AM5, while the Intel part uses BGA 2540. The AMD chip is a desktop part, and the Intel chip is a mobile part. The AMD processor has 24 PCIe Gen 5 lanes from the CPU, whereas the Intel processor has only 4 Gen 5 lanes. Integrated graphics also differ: AMD includes Radeon Graphics, while Intel includes Arc B390.

Specification Differences

The specification table reveals several key differences beyond architecture. The AMD Ryzen 9 9900X3D has a base clock of 4.40 GHz and a boost clock of 5.50 GHz. The Intel Core Ultra X9 378H has a base clock of 2.00 GHz and a boost clock of 5.00 GHz. Thermal design power differs substantially: the AMD part has a TDP of 120, while the Intel part has a TDP of 25. This reflects the mobile versus desktop positioning.

Memory support and bandwidth also differ. The AMD part supports DDR5 with a memory bandwidth of 89.6 GB/s, and it supports ECC memory. The Intel part supports LPDDR5X with a higher memory bandwidth of 153.6 GB/s, but it does not support ECC memory. The PCIe lane count is a major differentiator: AMD provides 24 CPU lanes, while Intel provides only 4 CPU lanes. The AMD processor has an unlocked multiplier, while the Intel processor does not. The AMD part has a recorded launch MSRP of $599; no launch MSRP is recorded for the Intel part.

Head-to-Head Benchmarks

The Cinebench suite shows a consistent pattern. In Cinebench R15 multicore, the AMD Ryzen 9 9900X3D scores 4811 against Intel's 3281, a 46.6% lead. The single-core R15 result is similar, with AMD at 679 and Intel at 462, a 47% lead. In Cinebench R20, AMD scores 20049 multicore and 2830 single-core, versus Intel's 13672 and 1929, with deltas of 46.6% and 46.7% respectively. Cinebench R23 follows the same trend: AMD scores 47737 multicore and 6739 single-core, while Intel scores 32553 and 4595, with deltas of 46.6% and 46.7%.

The PassMark suite provides the largest single margin. In integer math, AMD scores 179727 against Intel's 92603, a 94.1% advantage. Data compression shows AMD at 685074 versus Intel's 386591, a 77.2% lead. Extended instructions also show a 77% delta, with AMD at 55426 and Intel at 31315. The find prime numbers test gives AMD a 52.4% lead (544 versus 357), and random string sorting shows a 61% lead (71864 versus 44648).

The closest results are in the remaining PassMark tests. Floating-point math shows AMD at 119622 versus Intel's 114500, a narrow 4.5% lead. PassMark multithread shows AMD at 56154 versus Intel's 38298, a 46.6% lead. Physics shows AMD at 5340 versus Intel's 3404, a 56.9% lead. Data encryption shows AMD at 33282 versus Intel's 29840, an 11.5% lead. Single-thread tests show the smallest gap: AMD scores 4646 against Intel's 4453, a 4.3% delta in both recorded single-thread variants.

The Verdict

The recorded data points to a straightforward conclusion for raw performance: the AMD Ryzen 9 9900X3D is the faster processor in every measured metric. It wins all 17 head-to-head benchmarks, with an average score of 54762 compared to Intel's 47468. The largest margins are in integer math and data compression, where the AMD part more than doubles Intel's output in some cases. For workloads like video encoding, 3D rendering, or scientific computing that use Cinebench-style multi-threaded execution, the AMD chip delivers roughly 46.6% more performance across the board.

The Intel Core Ultra X9 378H is not without its strengths, but those strengths lie outside the benchmark suite. Its 25 TDP and 153.6 GB/s memory bandwidth indicate a focus on mobile efficiency. Its single-thread scores are within 4.3% of the AMD part, which is a strong result for a processor with a much lower power envelope. However, the database contains no benchmark where the Intel chip wins, and its 89th percentile rank versus AMD's 91st percentile confirms the overall gap.

For a desktop workstation or high-end gaming rig, the AMD Ryzen 9 9900X3D is the clear choice based on the data. For a mobile laptop where power draw and integrated graphics matter more than raw multi-threaded scores, the Intel Core Ultra X9 378H is the only viable option of the two, given its BGA 2540 socket and mobile market segment. The choice is not between two interchangeable parts; it is a choice between desktop performance and mobile mobility.