Intel Core Ultra 9 285K vs Intel Core Ultra X9 388H Comparison

Where Each One Wins

The benchmark split is completely one-sided. The Intel Core Ultra 9 285K wins all 17 recorded head-to-head comparisons against the Intel Core Ultra X9 388H, with zero wins for the mobile chip. This is not a near-tie where workloads favor one or the other; the desktop part dominates across every measured category, from single-threaded responsiveness to heavily parallel multi-threaded rendering.

The largest margins appear in multi-core and data-heavy workloads. In Cinebench R23 multi-core, the 285K scores 42522 against 18911 for the 388H, a 124.9% advantage. Cinebench R15 multi-core shows a similar gap at 119.8%, with scores of 6494 versus 2955. PassMark data compression tells the same story: 790052 versus 361763, a 118.4% delta. These are workloads where the 285K's higher core count and desktop power envelope translate directly into throughput advantages.

Single-threaded performance is closer but still favors the 285K. Cinebench R23 single-core shows only an 8% delta, with 2377 versus 2200.5. PassMark single-thread is an 18.9% gap, 5087 versus 4280. The 388H is competitive in lightly threaded work, which is expected given its 5.10 GHz boost clock. But the 285K's 5.70 GHz boost and architectural advantages still put it ahead in every single-threaded test recorded.

The smallest margin in the entire dataset is Cinebench R23 single-core at 8%. The largest is Cinebench R23 multi-core at 124.9%. Intermediate workloads like PassMark floating point math (99.3% delta), integer math (89.7%), and multithread (82.7%) all show the 285K roughly doubling or nearly doubling the 388H's output. Physics simulation is the closest multi-threaded test at 22.1%, with 3938 versus 3226.

Architecture Differences

The two processors come from different generations, different market segments, and different foundries. The 285K is a desktop part from the Core Ultra Series 2, built on the Arrow Lake architecture (Arrow Lake-S) and fabricated by TSMC on a 3 nm process. The 388H is a mobile part from Core Ultra Series 3, using the Panther Lake architecture (Panther Lake-H) and fabricated by Intel on a 3 nm process. Both use 3 nm lithography, but the foundry differs: TSMC for the desktop chip, Intel for the mobile chip.

Core counts diverge significantly. The 285K has 24 cores and 24 threads, meaning no hyperthreading. The 388H has 16 cores and 16 threads, also without hyperthreading. Both processors use a per-core cache structure with 192 KB of L1 and 3 MB of L2 per core. The shared L3 cache differs: the 285K has 36 MB shared, while the 388H has 18 MB shared. That is exactly half the L3 capacity.

Clock speeds reflect their roles. The 285K runs a 3.70 GHz base clock and boosts to 5.70 GHz. The 388H has a 2.10 GHz base clock and boosts to 5.10 GHz. The desktop part has a 125 TDP rating; the mobile part is rated at 25 TDP. That five-fold difference in power envelope explains much of the performance gap in sustained multi-core workloads.

Memory support is a clear differentiator. The 285K supports DDR5 with a dual-channel memory bus and 102.4 GB/s bandwidth. The 388H supports LPDDR5X, also dual-channel, but with 153.6 GB/s bandwidth. Despite the mobile chip's higher memory bandwidth, the desktop part's other advantages dominate in the recorded benchmarks. ECC memory is supported on the 285K but not on the 388H.

PCIe lanes also differ. The 285K provides Gen 5 with 20 lanes (CPU only). The 388H provides Gen 5 with 4 lanes (CPU only). The integrated graphics are different: the 285K uses Arc Xe-LPG Graphics with 64 execution units, while the 388H uses Arc B390. The desktop chip has an unlocked multiplier; the mobile chip does not. Sockets are incompatible: Intel Socket 1851 for the 285K versus Intel BGA 2540 for the 388H.

Release timing and market positioning also separate them. The 285K was released on 2024-10-23 with a launch MSRP of $589. The 388H was released on 2026-01-04 with no recorded launch MSRP. The 285K sits in the 96th percentile of all CPUs in the database; the 388H sits in the 88th percentile.

Head-to-Head Benchmarks

The Cinebench suite shows the 285K's multi-core dominance most starkly. In Cinebench R15 multi-core, the 285K scores 6494 versus 2955, a 119.8% lead. Cinebench R20 multi-core shows 24003 versus 13101, an 83.2% lead. Cinebench R23 multi-core is the largest gap in the dataset: 42522 versus 18911, a 124.9% delta. Single-core results in Cinebench are much tighter. R15 single-core gives 359 versus 309.5, a 16% lead. R20 single-core shows 3388 versus 1849, an 83.2% delta, which is unusually large for a single-threaded test. R23 single-core narrows to 2377 versus 2200.5, just 8% apart.

PassMark tests cover a broader range of workloads. Data compression heavily favors the 285K: 790052 versus 361763, a 118.4% delta. Data encryption shows 57745 versus 28490, a 102.7% lead. Extended instructions score 62277 versus 29943, a 108% gap. Prime number finding gives 541 versus 358, a 51.1% lead, which is the smallest multi-core PassMark margin. Floating point math scores 224324 versus 112550, a 99.3% delta, nearly doubling the mobile chip. Integer math shows 172379 versus 90882, an 89.7% lead. The multithread score is 67260 versus 36811, an 82.7% delta. Physics is closer: 3938 versus 3226, a 22.1% lead. Random string sorting shows 94927 versus 44010, a 115.7% delta.

Single-threaded PassMark results are recorded twice in the dataset, with both passmark_single_thread and passmark_singlethread showing identical scores: 5087 for the 285K and 4280 for the 388H, an 18.9% lead. This consistency confirms the single-thread advantage is real but modest compared to the multi-core margins.

The overall average benchmark score in the database reflects the same hierarchy. The 285K averages 83807 across all recorded benchmarks, while the 388H averages 44466. That is roughly an 88.5% higher average for the desktop chip. The nearest rivals for each processor reinforce their positioning: the 285K sits near the AMD EPYC 4584PX (0.9% delta) and AMD EPYC 9135 (1% delta), while the 388H sits near the AMD Ryzen 5 7500X3D (-0.2% delta) and Intel Core i9-13950HX (0.3% delta).

FAQ

Q: Which processor has more cores and threads?

A: The Intel Core Ultra 9 285K has 24 cores and 24 threads. The Intel Core Ultra X9 388H has 16 cores and 16 threads. Neither processor uses hyperthreading, so thread counts equal core counts.

Q: How do their clock speeds compare?

A: The 285K has a 3.70 GHz base clock and a 5.70 GHz boost clock. The 388H has a 2.10 GHz base clock and a 5.10 GHz boost clock. The desktop chip boosts 0.60 GHz higher.

Q: What is the biggest performance gap between the two?

A: The largest recorded delta is in Cinebench R23 multi-core, where the 285K leads by 124.9% with a score of 42522 versus 18911. PassMark data compression is nearly as large at 118.4%.

Q: Is the mobile chip competitive in single-threaded workloads?

A: Somewhat. The smallest margin in the dataset is Cinebench R23 single-core, where the 285K leads by only 8% (2377 versus 2200.5). Cinebench R15 single-core shows a 16% lead for the 285K, and PassMark single-thread shows an 18.9% lead.

Q: Do they support the same memory types?

A: No. The 285K supports DDR5 with 102.4 GB/s bandwidth. The 388H supports LPDDR5X with 153.6 GB/s bandwidth. Both use dual-channel memory buses, but the mobile chip has higher memory bandwidth.

Q: Which processor has a higher database percentile ranking?

A: The 285K ranks in the 96th percentile of all CPUs, while the 388H ranks in the 88th percentile. The 285K's average benchmark score is 83807, compared to 44466 for the 388H.

The Verdict

The data leaves no ambiguity. The Intel Core Ultra 9 285K is faster than the Intel Core Ultra X9 388H in every recorded benchmark. The desktop chip wins all 17 head-to-head comparisons, with margins ranging from 8% in Cinebench R23 single-core to 124.9% in Cinebench R23 multi-core. Anyone needing maximum multi-threaded throughput for rendering, data compression, encryption, or floating point math should choose the 285K based on the recorded scores.

The 388H is not without merit. Its 25 TDP rating and mobile form factor (Intel BGA 2540 socket) make it suitable for portable systems where power draw and heat dissipation are constrained. Its 153.6 GB/s memory bandwidth exceeds the 285K's 102.4 GB/s, which could matter in memory-bound mobile workloads even though the recorded benchmarks do not show a win. Its 5.10 GHz boost clock keeps single-threaded performance within 8% to 18.9% of the desktop chip, depending on the test.

The 285K's advantages are structural. It has 8 more cores, 18 MB more shared L3 cache, a 0.60 GHz higher boost clock, a 100 W higher TDP, and 16 more PCIe Gen 5 lanes. It also supports ECC memory and has an unlocked multiplier, features absent from the 388H. The 285K uses TSMC's 3 nm process, while the 388H uses Intel's 3 nm process, though both are 3 nm.

For desktop users with power headroom and cooling capacity, the 285K is the clear choice. Its 96th percentile ranking versus the 388H's 88th percentile, combined with an average benchmark score nearly double that of the mobile chip, confirms its superiority in the recorded data. For mobile users prioritizing battery life and portability, the 388H is the only option in this comparison, as the 285K is a desktop part with no mobile socket compatibility.

The competitive context reinforces the split. The 285K's nearest rivals include server-class AMD EPYC processors (4584PX within 0.9%, 9135 within 1%), indicating it competes at the high end of desktop and entry server performance. The 388H's nearest rivals include the AMD Ryzen 5 7500X3D (-0.2%) and Intel Core i9-13950HX (0.3%), placing it in the upper-mid mobile and desktop range. Neither chip's rival list overlaps, confirming they target different performance tiers entirely.

Specification Differences

The following fields differ between the two processors:

• Series: Core Ultra Series 2 (285K) versus Core Ultra Series 3 (388H)
• Cores: 24 versus 16
• Threads: 24 versus 16
• Base clock: 3.70 GHz versus 2.10 GHz
• Boost clock: 5.70 GHz versus 5.10 GHz
• TDP: 125 versus 25
• Socket: Intel Socket 1851 versus Intel BGA 2540
• Architecture: Arrow Lake versus Panther Lake
• Codename: Arrow Lake-S versus Panther Lake
• Generation: Ultra 9 (Arrow Lake) versus Ultra X9 (Panther Lake-H)
• Foundry: TSMC versus Intel
• Transistors: 17,800 million versus not recorded
• Die size: 243 mm² versus not recorded
• L3 cache: 36 MB shared versus 18 MB shared
• Memory support: DDR5 versus LPDDR5X
• Memory bandwidth: 102.4 GB/s versus 153.6 GB/s
• ECC memory: Supported versus not supported
• PCIe: Gen 5, 20 lanes versus Gen 5, 4 lanes
• Integrated graphics: Arc Xe-LPG Graphics 64EU versus Arc B390
• Market segment: Desktop versus Mobile
• Release date: 2024-10-23 versus 2026-01-04
• Launch MSRP: $589 versus not recorded
• Multiplier unlocked: Yes versus No
• Part number: SRQD5 versus SA4QWQ9EK