AMD Ryzen 9 7945HX vs AMD Ryzen AI Max 390 Comparison

The AMD Ryzen AI Max 390 and AMD Ryzen 9 7945HX represent two distinct approaches to high-end mobile computing, separated by a generation of architecture and a fundamental difference in design philosophy. While both processors target the same performance percentile—sitting at the 94th percentile of all CPUs—their benchmark results reveal a clear split: the Ryzen 9 7945HX dominates in raw multi-threaded throughput, whereas the Ryzen AI Max 390 shows surprising strength in specific single-threaded and physics-based workloads. The data shows a 0.5% difference in average benchmark scores, with the Ryzen AI Max 390 scoring 57103 versus the Ryzen 9 7945HX's 56802, making this a remarkably close contest on paper despite the divergent hardware underneath.

FAQ

Q: Which processor has the higher average benchmark score?

A: The AMD Ryzen AI Max 390 edges out the Ryzen 9 7945HX with an average benchmark score of 57103 compared to 56802, a 0.5% difference. Both CPUs rank in the 94th percentile of all processors.

Q: How large is the performance gap in multi-core Cinebench tests?

A: The Ryzen 9 7945HX leads by exactly 22.2% across Cinebench R15, R20, and R23 multi-core tests. For example, in Cinebench R23 multi-core, the 7945HX scores 46375 versus the AI Max 390's 36064.

Q: Does the Ryzen AI Max 390 win any benchmark categories?

A: Yes, it wins two of the 17 head-to-head tests. It beats the Ryzen 9 7945HX by 13.4% in PassMark find prime numbers (322 vs 284) and by 10.2% in PassMark physics (2754 vs 2500).

Q: What is the single-thread performance difference between the two?

A: The single-thread scores are nearly identical. In PassMark single-thread, the Ryzen 9 7945HX scores 4040 versus 4025 for the AI Max 390, a mere 0.4% difference. However, in Cinebench R23 single-core, the gap widens to 22.2%, favoring the 7945HX with 6547 versus 5091.

Q: Which processor has more cores and threads?

A: The AMD Ryzen 9 7945HX has 16 cores and 32 threads, while the AMD Ryzen AI Max 390 has 12 cores and 24 threads. The Ryzen 9 7945HX also has a higher boost clock of 5.40 GHz compared to 5.00 GHz.

Q: How do their memory systems differ?

A: The Ryzen AI Max 390 uses quad-channel LPDDR5X memory with 256.0 GB/s bandwidth, while the Ryzen 9 7945HX uses dual-channel DDR5 with 83.2 GB/s bandwidth. This gives the AI Max 390 over three times the memory bandwidth.

Architecture Differences

The fundamental architectural split is clear: the Ryzen AI Max 390 is built on Zen 5 architecture using a 4 nm process, while the Ryzen 9 7945HX uses Zen 4 on a 5 nm process, both fabricated by TSMC. This process advantage allows the AI Max 390 to achieve its 3.20 GHz base clock despite its higher transistor density, though the 7945HX counters with a 5.40 GHz boost clock versus 5.00 GHz.

The cache layouts differ per core. The AI Max 390 allocates 80 KB of L1 cache per core and 1 MB of L2 per core, while the 7945HX uses 64 KB of L1 and 1 MB of L2 per core. Both share 64 MB of L3 cache, but the AI Max 390's Zen 5 architecture benefits from a larger per-core L1 allocation, which contributes to its physics and prime number test wins.

Memory architecture is where the designs diverge most dramatically. The AI Max 390 employs quad-channel LPDDR5X with a 256.0 GB/s memory bus, versus the 7945HX's dual-channel DDR5 at 83.2 GB/s. This 3x bandwidth advantage for the AI Max 390 is offset by the 7945HX's superior PCIe implementation: Gen 5 with 28 lanes versus Gen 4 with 16 lanes on the AI Max 390. Both support ECC memory.

The integrated graphics also differ significantly. The AI Max 390 features the Radeon 8050S, while the 7945HX ships with the Radeon 610M. The AI Max 390 uses the AMD Socket FP11, whereas the 7945HX uses AMD Socket FL1. The 7945HX has an unlocked multiplier, and its die size is 2x 71 mm² with 13,140 million transistors; the AI Max 390's die is 2x 70.6 mm² with transistor count not specified.

Where Each One Wins

The Ryzen 9 7945HX is the clear winner for multi-threaded productivity and content creation. It wins 15 of the 17 head-to-head benchmarks, including all Cinebench tests, where it maintains a consistent 22.2% lead across R15, R20, and R23 in both single-core and multi-core modes. This extends to PassMark integer math, floating-point math, data compression, encryption, extended instructions, random string sorting, and multithread tests. For workloads like video rendering, 3D modeling, and software compilation, the 7945HX's 16 cores deliver decisive advantages—its Cinebench R23 multi-core score of 46375 versus 36064 represents a substantial capacity difference.

The Ryzen AI Max 390 wins in two specific niche areas. Its 13.4% advantage in PassMark find prime numbers (322 vs 284) indicates superior per-core integer processing in certain algorithmic patterns, likely from Zen 5's improved execution resources. The 10.2% lead in PassMark physics (2754 vs 2500) suggests better handling of physics simulation workloads, which often benefit from the larger L1 cache and memory bandwidth. For gaming physics or scientific simulations that stress these specific instruction patterns, the AI Max 390 offers a measurable edge.

The single-thread comparison is essentially a tie in PassMark (4040 vs 4025, a 0.4% difference), but the 7945HX dominates in Cinebench single-core tests with a 22.2% lead. This divergence suggests the 7945HX's higher boost clock benefits certain workloads more than others. The AI Max 390's wins are narrow but real, indicating that its architectural improvements in Zen 5 provide tangible benefits in select scenarios despite fewer cores.

Specification Differences

The two processors differ across nearly every core specification. Core count: 12 cores and 24 threads for the AI Max 390 versus 16 cores and 32 threads for the 7945HX. Base clock: 3.20 GHz versus 2.50 GHz, favoring the AI Max 390. Boost clock: 5.00 GHz versus 5.40 GHz, favoring the 7945HX. The TDP is identical at 55 watts for both.

Architecture and process node differ: Zen 5 on 4 nm for the AI Max 390, Zen 4 on 5 nm for the 7945HX. Cache configuration: 80 KB L1 per core for the AI Max 390 versus 64 KB per core for the 7945HX; both have 1 MB L2 per core and 64 MB shared L3. Die size is nearly identical at 2x 70.6 mm² versus 2x 71 mm², but the 7945HX lists 13,140 million transistors while the AI Max 390's count is unspecified.

Memory support is exclusive: LPDDR5X quad-channel with 256.0 GB/s bandwidth for the AI Max 390, DDR5 dual-channel with 83.2 GB/s for the 7945HX. PCIe generation and lane count differ: Gen 4 with 16 lanes versus Gen 5 with 28 lanes. Sockets are different: FP11 versus FL1. The 7945HX has an unlocked multiplier; the AI Max 390 does not. Integrated graphics differ: Radeon 8050S versus Radeon 610M. Release dates also separate them: January 2025 for the AI Max 390 versus January 2023 for the 7945HX.

Head-to-Head Benchmarks

The Cinebench suite shows the most dramatic and consistent gap. Across all six Cinebench tests (R15, R20, R23, each in single-core and multi-core), the Ryzen 9 7945HX wins by exactly 22.2%. In Cinebench R15 multi-core, the 7945HX scores 4674 versus 3635; in single-core, 659 versus 513. R20 multi-core sees 19477 versus 15146, and single-core 2749 versus 2138. R23 multi-core delivers 46375 versus 36064, while single-core produces 6547 versus 5091. This uniformity suggests a consistent architectural efficiency advantage for the 7945HX in rendering workloads.

The PassMark suite reveals where the 7945HX's extra cores pay off most. Data compression shows a 30.2% lead (707249 vs 493517), while data encryption demonstrates a 39.8% advantage (42703 vs 25692)—the largest delta in the entire comparison. Integer math trails by 28.3% (207524 vs 148707), and floating-point math by 24.1% (123390 vs 93598). Extended instructions show a 24.3% gap (51834 vs 39250), and random string sorting a 34.1% difference (81736 vs 53851). The multithread score follows the pattern with a 22.2% lead (54548 vs 42429).

The Ryzen AI Max 390's two wins are notable for their specificity. In PassMark find prime numbers, it scores 322 against 284, a 13.4% advantage that suggests Zen 5's branch prediction and integer execution improvements translate to real-world gains in prime-finding algorithms. In PassMark physics, it scores 2754 versus 2500, a 10.2% lead that may stem from its significantly higher memory bandwidth and larger L1 cache. The single-thread scores are nearly identical (4040 vs 4025, a 0.4% gap), indicating that at the single-thread level, the two architectures are closely matched in PassMark's testing methodology, despite the 7945HX's higher boost clock.