Intel Core i9-11900KB vs Intel Core i9-9920X Comparison

Head-to-Head Benchmarks

The recorded data shows a remarkably consistent pattern across the entire Cinebench suite: the Intel Core i9-9920X wins all six head-to-head matchups, yet the margins are surprisingly narrow given the architectural gap. In the Cinebench R15 multi-core test, the 9920X scores 2121 against 1946 for the 11900KB, a 9% advantage. The single-core result in the same test shows 299 versus 274, a 9.1% edge. These are not dominant victories; they are consistent, modest leads.

Moving to Cinebench R20, the same story repeats. The 9920X posts 8839 in multi-core, while the 11900KB manages 8112, again a 9% delta. In single-core, 1247 beats 1145, an 8.9% margin. The Cinebench R23 results follow the identical trajectory: 21046 versus 19316 in multi-core (9% delta) and 2971 versus 2727 in single-core (8.9% delta). The near-identical deltas across every test iteration suggest a fundamental throughput difference rather than workload-specific behavior.

What stands out is that the 9920X wins single-core tests too, despite the 11900KB having a substantially higher boost clock. The 9920X boosts to 4.50 GHz, while the 11900KB reaches 5.30 GHz. Yet the older architecture still produces higher single-thread scores. This implies that per-clock efficiency, or some other architectural factor, more than compensates for the raw clock deficit. The database records no benchmark where the 11900KB wins, making this a clean sweep for the 9920X with six wins and zero for the rival.

The average benchmark scores reinforce this picture. The 9920X has an average score of 5917 across all recorded tests, while the 11900KB averages 5587. That is roughly a 5.9% overall gap, slightly smaller than the Cinebench-specific deltas because the Geekbench results are included only for the 9920X. The 9920X sits at the 61st percentile among all CPUs, and the 11900KB also sits at the 61st percentile, meaning both occupy the same overall performance tier despite the 9920X winning every direct comparison.

Architecture Differences

The two processors come from entirely different design philosophies. The 9920X is built on the Skylake-X architecture using a 14 nm process node, while the 11900KB uses the Tiger Lake-H architecture on Intel's 10 nm node. The die sizes differ dramatically: the 9920X measures 484 mm², more than 2.5 times the 190 mm² die of the 11900KB. This size difference reflects the 9920X's additional cores and its desktop-oriented design.

Core counts tell a clear story. The 9920X packs 12 cores and 24 threads, whereas the 11900KB has 8 cores and 16 threads. That is a 50% core advantage for the 9920X, yet the benchmark deltas never exceed 9.1%. The 11900KB counters with a higher boost clock: 5.30 GHz against 4.50 GHz. The base clocks are closer, 3.30 GHz versus 3.50 GHz, favoring the 9920X slightly at idle or lightly threaded loads.

Cache hierarchies differ in structure. The 9920X has 64 KB of L1 cache per core, 1 MB of L2 per core, and 19.25 MB of shared L3. The 11900KB has 80 KB of L1 per core, 1.25 MB of L2 per core, and 24 MB of shared L3. The 11900KB has more L3 cache overall, yet it still loses multi-core tests, suggesting the 9920X's extra cores matter more than the larger shared cache.

Memory architecture presents a stark contrast. The 9920X supports quad-channel DDR4 memory with a theoretical bandwidth of 85.3 GB/s. The 11900KB is limited to dual-channel DDR4 with 51.2 GB/s. That is a 66% bandwidth advantage for the 9920X, which likely contributes to its multi-core wins in cache-heavy workloads. Neither processor supports ECC memory, and both have unlocked multipliers.

PCIe connectivity also differs. The 9920X provides 44 PCIe Gen 3 lanes from the CPU, while the 11900KB offers 20 PCIe Gen 4 lanes. The 9920X has far more lanes for expansion, but the 11900KB supports a newer standard. The 11900KB includes integrated UHD Graphics 750, while the 9920X has no integrated graphics, requiring a discrete GPU.

The sockets are incompatible: the 9920X uses Intel Socket 2066, a desktop HEDT platform, while the 11900KB uses Intel BGA 1787, a soldered mobile package. The 9920X is a desktop part with a 165 W TDP; the 11900KB is a mobile part with a 65 W TDP. The production status for both is end-of-life, and both are marked as mobile or desktop segments respectively.

FAQ

Q: Which processor wins more benchmarks in the database?

A: The Intel Core i9-9920X wins all six head-to-head benchmarks recorded against the 11900KB, with deltas ranging from 8.9% to 9.1%. The 11900KB records no wins in any direct comparison.

Q: Does the 11900KB's higher boost clock give it a single-core advantage?

A: No. Despite boosting to 5.30 GHz versus 4.50 GHz for the 9920X, the 11900KB loses every single-core test. In Cinebench R23 single-core, the 9920X scores 2971 against 2727, an 8.9% lead.

Q: How do the core counts compare?

A: The 9920X has 12 cores and 24 threads, while the 11900KB has 8 cores and 16 threads. The 9920X also has a 9% multi-core advantage in Cinebench R23.

Q: What memory bandwidth does each processor support?

A: The 9920X supports quad-channel DDR4 with 85.3 GB/s bandwidth. The 11900KB supports dual-channel DDR4 with 51.2 GB/s.

Q: Are both processors still in production?

A: No. The database lists both as end-of-life products. The 9920X was released in October 2018, while the 11900KB has no recorded release date.

Q: Do both processors have integrated graphics?

A: No. The 11900KB includes UHD Graphics 750. The 9920X has no integrated graphics, so it requires a separate discrete GPU.

Specification Differences

The two CPUs differ in nearly every major specification category. The 9920X uses the Skylake architecture on a 14 nm node with a 484 mm² die. The 11900KB uses Tiger Lake on a 10 nm node with a 190 mm² die. Core counts differ: 12 versus 8, with threads at 24 versus 16. Base clocks are close, 3.50 GHz versus 3.30 GHz, but boost clocks favor the 11900KB at 5.30 GHz versus 4.50 GHz.

TDP is a significant differentiator: 165 W for the 9920X versus 65 W for the 11900KB. The sockets are entirely different, with the 9920X on Intel Socket 2066 and the 11900KB on Intel BGA 1787. Cache configurations differ in both per-core and shared allocations. The L1 cache is 64 KB per core on the 9920X and 80 KB per core on the 11900KB. L2 is 1 MB per core versus 1.25 MB per core. L3 is 19.25 MB shared versus 24 MB shared.

Memory support is quad-channel on the 9920X and dual-channel on the 11900KB, with bandwidth of 85.3 GB/s versus 51.2 GB/s. PCIe support differs: Gen 3 with 44 lanes on the 9920X, Gen 4 with 20 lanes on the 11900KB. The 11900KB has integrated UHD Graphics 750; the 9920X has none. The market segments differ, with the 9920X classified as desktop and the 11900KB as mobile. Both have unlocked multipliers, both lack ECC support, and both are end-of-life. The 9920X carries a launch MSRP of $1189, while the 11900KB has a launch MSRP of $539.

The Verdict

The data points clearly toward the Intel Core i9-9920X as the stronger performer in every recorded benchmark. It wins all six head-to-head tests, with consistent 9% deltas across multi-core and single-core workloads. The 50% core advantage (12 versus 8) and the 66% memory bandwidth advantage (85.3 GB/s versus 51.2 GB/s) likely explain the multi-core wins. The single-core wins are more surprising given the 11900KB's higher boost clock, suggesting the Skylake-X architecture's per-core efficiency or memory subsystem plays a decisive role.

However, the 11900KB is not without merit. Its 65 W TDP versus 165 W TDP represents a substantial power efficiency advantage, and its integrated UHD Graphics 750 eliminates the need for a separate GPU. The 24 MB of L3 cache is larger than the 9920X's 19.25 MB. The 10 nm process node is newer than the 14 nm node, and the Gen 4 PCIe support offers faster connectivity for compatible devices.

The 9920X is the choice for raw performance, particularly in multi-threaded workloads where its extra cores and memory bandwidth shine. The 11900KB is the choice for compact, power-conscious systems where the lower TDP and integrated graphics matter more than peak benchmark scores. Both sit at the 61st percentile among all CPUs, so either will deliver competitive performance, but the 9920X consistently outperforms the 11900KB in the recorded tests.

Where Each One Wins

The 9920X wins in all six recorded benchmarks, making it the clear choice for performance-focused builds. Its quad-channel memory and 12 cores provide a strong foundation for multi-threaded rendering, video encoding, and scientific computing. The 9% multi-core lead in Cinebench R23 (21046 versus 19316) demonstrates its advantage in heavily parallel workloads. The single-core wins, though smaller at 8.9% to 9.1%, show that even lightly threaded tasks favor the 9920X in this dataset.

The 11900KB's advantages are not measured in benchmark scores but in system-level characteristics. Its 65 W TDP makes it suitable for thermally constrained environments like small-form-factor or mobile platforms. The integrated UHD Graphics 750 provides display output without a discrete GPU, reducing system cost and complexity. The 24 MB L3 cache and 10 nm process represent newer technology, and the Gen 4 PCIe lanes offer higher per-lane bandwidth for modern SSDs and GPUs.

For users choosing between these two, the decision hinges on priorities. If benchmark performance is the sole criterion, the 9920X wins every test. If power consumption, integrated graphics, and platform flexibility matter more, the 11900KB offers a compelling alternative despite its lower scores. The 9920X's end-of-life status and high launch MSRP of $1189 reflect its HEDT positioning, while the 11900KB's $539 launch MSRP and mobile socket suggest a different intended use case. The database shows a clear performance hierarchy, but the right choice depends on the system's broader requirements.