Intel Core i9-11900T vs Intel Core i9-9900KS Comparison

# Intel Core i9-9900KS vs Intel Core i9-11900T

The Intel Core i9-9900KS and Intel Core i9-11900T represent two very different approaches to the same 8-core, 16-thread formula. The 9900KS is a special-edition Coffee Lake part engineered for maximum clock speed, while the 11900T is a low-power Rocket Lake chip designed to sip electricity. The benchmark data shows a clear split: the older 9900KS dominates most multi-threaded and Cinebench workloads, but the newer 11900T wins decisively in single-threaded Geekbench performance. The 9900KS takes 7 of 8 head-to-head benchmark wins, yet the one loss is significant enough to change how you should think about these two processors.

Head-to-Head Benchmarks

The most striking result in the head-to-head comparison is Geekbench single-core, where the i9-11900T scores 2157 against the 9900KS's 1715 — a 20.5% margin in favor of the Rocket Lake chip. This is the largest delta in the entire comparison and shows that Intel's newer architecture brings substantial per-thread improvements despite lower clock speeds. The 11900T's boost clock of 4.90 GHz is barely below the 9900KS's 5.00 GHz, but the architectural IPC gains from Rocket Lake are evident in this test.

However, the 9900KS strikes back in Geekbench multi-core with a score of 9771 versus 8257 for the 11900T — an 18.3% advantage. This is the second-largest gap in the comparison and demonstrates that the 9900KS's higher sustained clocks under load matter more than architectural efficiency when all 8 cores are active. The 9900KS maintains a 4.00 GHz base clock against the 11900T's extremely low 1.50 GHz base, which explains why the older chip pulls ahead when workloads scale across all cores.

In Cinebench tests, the pattern is consistent but narrower. The 9900KS wins R15 multi-core with 1657 against 1572, a 5.4% margin. Single-core R15 shows the same 5.4% gap, with scores of 233 and 221. Moving to R20, the multi-core result is 6907 versus 6550 (5.5% advantage for the 9900KS), and single-core is 974 versus 924 (again 5.4%). The R23 results maintain this exact pattern: multi-core 16446 versus 15596 (5.5%) and single-core 2321 versus 2201 (5.5%). The consistency of these Cinebench deltas suggests that the 9900KS's higher sustained clocks provide a uniform advantage in this rendering workload, regardless of thread count.

The average benchmark scores tell a similar story. The 9900KS averages 4738 across all benchmark results, placing it at the 59th percentile of all CPUs. The 11900T averages 4685, good for the 58th percentile. These are nearly identical overall performance levels, differing by just over 1%. The nearest rival data reinforces this: the 9900KS sits within 0.1% of the Intel Core i7-6950X and 0.6% of the Core i9-10900E, while the 11900T is 0.5% ahead of the Core i9-10900F and 1% behind the Core i7-6950X. Both chips occupy essentially the same performance tier, but they reach it through different means.

FAQ

Q: Which processor is faster in single-threaded workloads?

A: The Intel Core i9-11900T wins Geekbench single-core with 2157 versus 1715 for the 9900KS, a 20.5% advantage. However, in Cinebench R15, R20, and R23 single-core tests, the 9900KS is consistently 5.4-5.5% faster, scoring 233, 974, and 2321 respectively versus 221, 924, and 2201 for the 11900T.

Q: How do the two chips compare in multi-core performance?

A: The 9900KS wins every multi-core benchmark in the comparison. Geekbench multi-core shows the biggest gap at 9771 versus 8257 (18.3%), while Cinebench R15, R20, and R23 multi-core tests all show the 9900KS ahead by 5.4-5.5%, with scores of 1657 versus 1572, 6907 versus 6550, and 16446 versus 15596 respectively.

Q: What are the power and clock differences?

A: The 9900KS has a 127W TDP with 4.00 GHz base and 5.00 GHz boost clocks. The 11900T has a 35W TDP with 1.50 GHz base and 4.90 GHz boost clocks. The 11900T's base clock is dramatically lower, which explains its efficiency rating, but its boost clock nearly matches the 9900KS.

Q: Do both processors support the same memory configuration?

A: Both support DDR4 memory in dual-channel mode, but with different bandwidth ratings. The 9900KS has 42.7 GB/s memory bandwidth, while the 11900T offers 51.2 GB/s. Neither supports ECC memory.

Q: Which chip has better integrated graphics?

A: The 11900T features UHD Graphics 750, while the 9900KS has UHD 630. The 11900T's newer iGPU is part of the Rocket Lake architecture, representing a generation leap over the older Coffee Lake graphics solution.

Q: What PCIe capabilities do these processors offer?

A: The 9900KS provides PCIe Gen 3 with 16 lanes from the CPU. The 11900T offers PCIe Gen 4 with 20 lanes from the CPU, giving it both a newer standard and more total lanes for expansion.

Architecture Differences

The two chips come from different Intel architectures despite sharing the 14nm process node and Intel as the foundry. The 9900KS uses Coffee Lake, specifically the Coffee Lake-R refresh, while the 11900T is built on Rocket Lake. This architectural difference is visible in the cache hierarchy: the 9900KS has 64 KB of L1 cache per core and 256 KB of L2 per core, while the 11900T increases these to 80 KB and 512 KB per core respectively. Both share 16 MB of L3 cache across all cores.

The die sizes differ substantially. The 9900KS has a 180 mm² die, while the 11900T's die is 276 mm². This larger die reflects the more complex Rocket Lake architecture, which implements a newer core design on the mature 14nm process. The socket requirements also change: the 9900KS uses Intel Socket 1151, while the 11900T requires Intel Socket 1200, meaning these are not interchangeable in existing motherboards.

Integrated graphics represent another architectural divergence. The 9900KS ships with UHD 630, while the 11900T includes UHD Graphics 750. The newer iGPU in the 11900T benefits from the Rocket Lake architecture's improvements. PCIe support also advances with the architecture: the 9900KS is limited to Gen 3 with 16 CPU lanes, whereas the 11900T supports Gen 4 with 20 CPU lanes.

Memory bandwidth increases with the newer architecture. The 9900KS is rated at 42.7 GB/s, while the 11900T reaches 51.2 GB/s. This 20% improvement in theoretical bandwidth aligns with Rocket Lake's updated memory controller. The production status is identical — both are end-of-life products — but the release timing differs, with the 9900KS launching in October 2019 and the 11900T arriving in March 2021.

Specification Differences

The core and thread counts are identical: both processors offer 8 cores and 16 threads. Beyond that, nearly every other specification differs. Clock speeds show the 9900KS with a 4.00 GHz base against the 11900T's 1.50 GHz base — a massive difference. Boost clocks are closer, with 5.00 GHz on the 9900KS versus 4.90 GHz on the 11900T.

TDP is where the 11900T makes its case: 35W versus 127W for the 9900KS. This nearly 4x difference in thermal design power reflects the 11900T's low-power positioning. The socket changes from 1151 to 1200, and the architecture moves from Coffee Lake to Rocket Lake. The process node stays at 14nm, and both are fabricated by Intel.

Cache configurations differ in L1 and L2, with the 11900T offering 80 KB and 512 KB per core versus 64 KB and 256 KB per core on the 9900KS. L3 remains 16 MB shared on both. Memory support is DDR4 for both with dual-channel buses, but bandwidth differs as noted. PCIe generation and lane count both favor the 11900T. Integrated graphics are UHD 630 versus UHD Graphics 750.

The 9900KS has an unlocked multiplier, while the 11900T is locked. Launch MSRP differs: the 9900KS launched at $513, while the 11900T launched at $439. The 9900KS has part number SRG1Q, and the 11900T carries SRKNQ. Both are end-of-life desktop parts.

Where Each One Wins

The 9900KS is the clear winner for multi-threaded productivity workloads. It beats the 11900T by 18.3% in Geekbench multi-core and by 5.4-5.5% across all Cinebench multi-core tests. For users running rendering tasks, video encoding, or any workload that scales across all 8 cores, the 9900KS delivers measurably better performance. Its 127W TDP enables sustained high clocks, and the 5.00 GHz boost ceiling means even lightly threaded tasks get near-maximum frequency.

The 11900T wins in one specific but important area: Geekbench single-core performance. Its 2157 score versus 1715 represents a 20.5% advantage. This suggests that certain single-threaded applications that stress the latest instruction sets or benefit from architectural improvements will run noticeably better on the 11900T. The 35W TDP also makes it dramatically more suitable for compact or low-noise builds where heat dissipation is limited. The 11900T's PCIe Gen 4 support with 20 lanes provides modern expansion capability that the 9900KS cannot offer, and its 51.2 GB/s memory bandwidth is 20% higher.

For everyday mixed usage, the average benchmark scores are nearly identical — 4738 versus 4685 — so neither chip dominates general-purpose computing. The 9900KS edges ahead in overall average by about 1.1%, which is within the range of run-to-run variance. The choice between these two comes down to whether you prioritize raw multi-threaded output (9900KS) or single-thread efficiency and modern platform features (11900T).

The Verdict

The benchmark data presents a straightforward recommendation for most users: the Intel Core i9-9900KS is the better performer in the majority of workloads. It wins 7 of 8 head-to-head benchmarks, including every multi-core test and all three Cinebench versions. Its 5.4-5.5% advantage in Cinebench and 18.3% lead in Geekbench multi-core make it the stronger choice for anyone running heavily threaded applications. The 9900KS also offers an unlocked multiplier, which the 11900T lacks, giving enthusiasts headroom for manual overclocking.

The Intel Core i9-11900T is the choice for a specific niche: users who need the lowest possible power draw while maintaining competitive performance. Its 35W TDP is exceptional for an 8-core processor, and its 20.5% Geekbench single-core win shows that Rocket Lake's architecture delivers real per-thread gains. The 11900T also brings PCIe Gen 4, 20 CPU lanes, and higher memory bandwidth to the table, making it the more modern platform overall.

If raw performance is the priority and power consumption is not a concern, the 9900KS is the clear pick. If you need a low-power processor for a compact build, or if your primary applications are single-threaded and benefit from the newer architecture, the 11900T justifies its existence. Both chips sit at nearly the same overall performance level — 59th versus 58th percentile among all CPUs — so the decision hinges on your specific workload profile and system constraints rather than any overarching performance gap.