AMD Ryzen 9 3900 vs AMD Ryzen AI 9 HX PRO 375 Comparison

The AMD Ryzen 9 3900 and the AMD Ryzen AI 9 HX PRO 375 share an identical core and thread count, but the recorded data shows they could hardly be more different chips. The 3900 is a 65 W desktop part on the AM4 socket; the HX PRO 375 is a 28 W mobile part on Socket FP8 with integrated Radeon 890M graphics. Across thirteen head-to-head benchmarks, the newer mobile chip wins eleven, including a crushing single-thread victory, while the older desktop holds two narrow-to-solid wins. Both sit near the 90th percentile of all CPUs in the database, with average scores of 47918 for the 3900 and 47022 for the HX PRO 375, a spread of roughly two percent.

The Verdict

The data points in one clear direction for anything latency-sensitive. The HX PRO 375 posts a Cinebench R15 single-core score of 405 against 197 for the 3900, a gap the head-to-head data records at 51.4 percent in the mobile chip's favor, and its Passmark single-thread score of 3914 beats the 3900's 2604 by 33.5 percent. If the workload is interactive, lightly threaded, or dependent on per-core responsiveness, the HX PRO 375 is the pick. The 3900 still earns its place in two recorded scenarios: data encryption, where its 26657 beats 21186 by 25.8 percent, and prime number search, where 203 beats 125 by 62.4 percent. Its 65 W thermal envelope, unlocked multiplier, and Socket AM4 platform also make it the tunable desktop option, provided a discrete GPU is on hand, since it has no integrated graphics. The HX PRO 375 suits anyone needing a self-contained mobile solution: integrated graphics, DDR5 and LPDDR5X support, ECC memory, and a 4 nm process in a 28 W package.

Architecture Differences

These chips sit five process generations of AMD design apart. The 3900 is a Zen 2 "Matisse" design on TSMC's 7 nm node, released in 2019, built as two 74 mm² chiplets with 7,600 million transistors. The HX PRO 375 is a Zen 5 / Zen 5c "Strix Point" design on TSMC's 4 nm node, released in 2025, as a single 233 mm² die.

Thread resources are equal on paper: twelve cores and twenty-four threads each. Clock behavior is not. The 3900 runs a 3.10 GHz base and 4.30 GHz boost; the HX PRO 375 runs a 2.00 GHz base but boosts to 5.10 GHz. That 0.8 GHz boost advantage, combined with the newer architecture, explains the single-thread rout.

The cache story favors the desktop part in capacity and the mobile part in per-core locality. The 3900 pairs 64 KB of L1 and 512 KB of L2 per core with a large 64 MB L3 pool. The HX PRO 375 gives each core more L1 (80 KB) and more L2 (1 MB), but only 16 MB of L3. Workloads that fit in that big L3, such as some encryption and integer routines, play to the 3900's strengths.

Memory and platform differ sharply. The 3900 supports DDR4 on a dual-channel bus at 51.2 GB/s, with PCIe Gen 4 at 24 CPU lanes. The HX PRO 375 supports DDR5 and LPDDR5X, dual-channel, at 89.6 GB/s, with PCIe Gen 4 at 16 CPU lanes, and it adds ECC support plus integrated Radeon 890M graphics. The 3900's multiplier is unlocked; the HX PRO 375's is not. The 3900 carried a launch MSRP of $499.

Head-to-Head Benchmarks

The single-thread results are the headline. Cinebench R15 single-core: 405 versus 197, a 51.4 percent win for the HX PRO 375. Passmark single-thread confirms it independently: 3914 versus 2604, a 33.5 percent gap. This is the largest divide in the dataset and it colors nearly every lightly threaded workload.

Multi-core is far closer. Cinebench R15 multi-core goes to the HX PRO 375 by just 2.5 percent, 2875 versus 2804. Passmark Multithread shows a wider 9.2 percent margin, 33689 against 30586. Physics favors the mobile chip by 12.3 percent, 1843 to 1617. The takeaway: a 28 W Zen 5 design trading blows with a 65 W twelve-core desktop in throughput is the remarkable part, and edging ahead of it in every multi-core test is more remarkable still.

Compute subtests split along architectural lines. Floating point math: 74626 to 56730 for the HX PRO 375, up 24 percent. Integer math: 119521 to 97698, an 18.3 percent margin. Extended instructions: 29351 to 26073, 11.2 percent. The Zen 5 cores simply do more work per cycle in these paths.

The 3900's two wins are real. Data encryption lands at 26657 versus 21186, a 25.8 percent advantage likely tied to that 64 MB L3 and sustained multi-core throughput. Prime number search is its strongest result anywhere: 203 versus 125, a 62.4 percent win. Two near-ties round out the card: data compression goes to the HX PRO 375 by 0.6 percent (416331 versus 413887) and string sorting by 1 percent (45358 versus 44902).

Context from the rivals list reinforces how even these chips are overall. The 3900's average score of 47918 lands it dead level with the AMD Ryzen 9 7900X3D (47908, 0 percent delta), half a percent ahead of the Intel Core Ultra 7 265T, and half a percent behind the AMD Ryzen AI Max PRO 380. The HX PRO 375's 47022 sits a tenth of a percent from the AMD Ryzen 9 5900, 0.3 percent ahead of the Intel Core i7-13700K, and within 0.6 percent of the Intel Core i7-13700KF and Intel Core i9-12900F.

FAQ

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

A: The HX PRO 375, decisively. It wins Cinebench R15 single-core by 51.4 percent (405 vs 197) and Passmark single-thread by 33.5 percent (3914 vs 2604).

Q: Which is faster overall in multi-core?

A: The HX PRO 375. It leads Cinebench R15 multi-core by 2.5 percent (2875 vs 2804) and Passmark Multithread by 9.2 percent (33689 vs 30586), despite a 28 W TDP versus 65 W.

Q: Does either chip have integrated graphics?

A: The HX PRO 375 includes Radeon 890M graphics. The 3900 has none and requires a discrete GPU.

Q: Can both chips be overclocked?

A: No. The 3900 has an unlocked multiplier; the HX PRO 375 does not.

Q: Which has more cache?

A: The 3900, in L3: 64 MB versus 16 MB. The HX PRO 375 has more L1 (80 KB vs 64 KB per core) and L2 (1 MB vs 512 KB per core).

Q: Do they support the same memory?

A: No. The 3900 supports DDR4 at 51.2 GB/s. The HX PRO 375 supports DDR5 and LPDDR5X at 89.6 GB/s and adds ECC, which the 3900 lacks.

Where Each One Wins

The HX PRO 375 owns responsiveness and modern compute. Anything dominated by a few fast threads, from application launches to browser workloads, benefits from its 5.10 GHz boost and Zen 5 cores, as the 51.4 percent single-core lead shows. Floating point, integer, and SIMD-heavy processing all go its way (24, 18.3, and 11.2 percent respectively), as do physics (12.3 percent) and general multithreading (9.2 percent). Its higher 89.6 GB/s memory bandwidth, ECC support, and self-contained Radeon 890M graphics make it the complete mobile platform for portable professional machines.

The 3900 wins where brute sustained throughput and cache capacity matter. Its 62.4 percent prime-search lead and 25.8 percent encryption lead show the value of 64 MB of L3 feeding twelve cores over long runs. As a desktop AM4 part with an unlocked multiplier and PCIe Gen 4 at 24 CPU lanes, it suits a fixed workstation with discrete graphics, a cooling solution sized for its 65 W TDP, and workloads like the two it tops. For everyone else, the recorded data favors the newer chip in eleven of thirteen tests.