Intel Core i7-9800X vs Intel Core i9-9900KF Comparison

Where Each One Wins

The recorded benchmark data splits these two processors into distinct personality profiles. The Intel Core i7-9800X dominates the Cinebench suite, winning all six Cinebench R15, R20, and R23 tests, both multi-core and single-core. Its margins are narrow, however, ranging from 0.8% to 0.9% across those tests. The i7-9800X takes the multi-core Cinebench R23 test with a score of 15416 against the i9-9900KF's 15292, and the single-core R23 test with 2176 versus 2158.

The Intel Core i9-9900KF, by contrast, wins decisively in the Geekbench tests. It scores 8970 in Geekbench multi-core, which is 19.8% ahead of the i7-9800X's 7488. In Geekbench single-core, the i9-9900KF scores 1706 versus 1398, a 22% lead. These are not marginal differences; they are substantial gaps that suggest the i9-9900KF has a significant advantage in workloads that Geekbench measures, which tend to be more latency-sensitive and less dependent on sustained multi-threaded throughput.

The use-case split is clear. For heavily threaded rendering workloads, the i7-9800X holds a slight but consistent edge across every Cinebench iteration. For general-purpose computing, office productivity, and applications that reward high single-thread responsiveness, the i9-9900KF is the stronger choice by a wide margin. The i9-9900KF also carries a higher boost clock of 5.00 GHz versus 4.50 GHz, which aligns with its Geekbench single-core dominance. The i7-9800X compensates with a higher base clock of 3.80 GHz versus 3.60 GHz, but the data shows this does not translate into single-core superiority in Geekbench.

In terms of overall average benchmark score, the i9-9900KF records 4652, placing it slightly ahead of the i7-9800X's 4455. Both processors sit at the 58th percentile among all CPUs in the database, meaning they occupy the same tier of overall performance, even though their strengths are distributed differently.

Architecture Differences

The architectural divide between these two chips is fundamental. The i9-9900KF uses the Coffee Lake architecture on the Coffee Lake-R codename, built on a 14 nm process with a die size of 180.3 mm². It fits into the Intel Socket 1151. The i7-9800X uses the Skylake architecture with the Skylake-X codename, also on a 14 nm process, but it requires the Intel Socket 2066. The i7-9800X belongs to the Core i7 X-Series 9th Gen, while the i9-9900KF belongs to the Core i9 Coffee Lake Refresh family.

Both processors have 8 cores and 16 threads, and both have their multipliers unlocked. The cache layouts differ meaningfully. The i9-9900KF carries 64 KB of L1 cache per core, 256 KB of L2 cache per core, and 16 MB of shared L3 cache. The i7-9800X also has 64 KB of L1 per core, but its L2 cache is 1 MB per core, four times larger, and its L3 cache is 16.5 MB shared. The larger per-core L2 on the i7-9800X is typical of the Skylake-X design, which was built for high-end desktop platforms with more generous cache hierarchies.

Memory support is another major divergence. The i9-9900KF uses dual-channel DDR4 memory with a recorded bandwidth of 42.7 GB/s. The i7-9800X uses quad-channel DDR4 memory with a recorded bandwidth of 85.3 GB/s, exactly double. This gives the i7-9800X a substantial theoretical memory bandwidth advantage, which likely contributes to its Cinebench wins, as rendering workloads often scale with memory throughput. However, the Geekbench results show that raw bandwidth does not always translate to better scores.

PCIe lane counts also differ sharply. The i9-9900KF provides Gen 3, 16 lanes from the CPU only. The i7-9800X provides Gen 3, 44 lanes from the CPU only. For users connecting multiple GPUs, NVMe drives, or other expansion cards, the i7-9800X offers far more headroom. Neither processor includes integrated graphics, so both require a discrete GPU.

The i7-9800X has a higher TDP of 165 watts, compared to 95 watts for the i9-9900KF. This reflects the more power-hungry Skylake-X design, with its larger cache and quad-channel memory controller. The i9-9900KF's lower TDP makes it easier to cool and more power-efficient under load.

FAQ

Q: Which processor has the higher boost clock?

A: The Intel Core i9-9900KF boosts to 5.00 GHz, while the Intel Core i7-9800X boosts to 4.50 GHz.

Q: Do both processors have the same core and thread count?

A: Yes, both have 8 cores and 16 threads.

Q: Which processor wins the most benchmarks in the head-to-head data?

A: The Intel Core i7-9800X wins 6 of the 8 recorded benchmarks, while the Intel Core i9-9900KF wins 2.

Q: What is the memory bandwidth difference between the two?

A: The i7-9800X has a memory bandwidth of 85.3 GB/s due to quad-channel memory, while the i9-9900KF has 42.7 GB/s with dual-channel memory.

Q: Which processor has a larger L2 cache per core?

A: The i7-9800X has 1 MB of L2 cache per core, compared to 256 KB per core on the i9-9900KF.

Q: Are both processors still in production?

A: No, both are marked as end-of-life in the database.

Specification Differences

The following specifications differ between the two processors:

• Base Clock: i9-9900KF at 3.60 GHz, i7-9800X at 3.80 GHz
• Boost Clock: i9-9900KF at 5.00 GHz, i7-9800X at 4.50 GHz
• TDP: i9-9900KF at 95 W, i7-9800X at 165 W
• Socket: i9-9900KF on Intel Socket 1151, i7-9800X on Intel Socket 2066
• Architecture: i9-9900KF on Coffee Lake, i7-9800X on Skylake
• Codename: i9-9900KF on Coffee Lake-R, i7-9800X on Skylake-X
• Generation: i9-9900KF in Core i9 (Coffee Lake Refresh), i7-9800X in Core i7 (X-Series 9th Gen)
• Die Size: i9-9900KF at 180.3 mm², i7-9800X not recorded
• L2 Cache: i9-9900KF at 256 KB per core, i7-9800X at 1 MB per core
• L3 Cache: i9-9900KF at 16 MB shared, i7-9800X at 16.5 MB shared
• Memory Bus: i9-9900KF dual-channel, i7-9800X quad-channel
• Memory Bandwidth: i9-9900KF at 42.7 GB/s, i7-9800X at 85.3 GB/s
• PCIe Lanes: i9-9900KF at Gen 3, 16 lanes, i7-9800X at Gen 3, 44 lanes
• Launch MSRP: i9-9900KF at $488, i7-9800X at $589
• Release Date: i9-9900KF on 2019-01-07, i7-9800X on 2018-10-18
• Part Number: i9-9900KF as SRG1ASRFAA, i7-9800X as SREZ9

Head-to-Head Benchmarks

The Cinebench results all favor the i7-9800X, but the margins are remarkably consistent. In Cinebench R15 multi-core, the i7-9800X scores 1553 against the i9-9900KF's 1541, a delta of -0.8%. In R15 single-core, the scores are 219 versus 217, a delta of -0.9%. The pattern holds in Cinebench R20 multi-core, where the i7-9800X scores 6474 versus 6422, again a -0.8% delta, and in R20 single-core with 913 versus 906, a -0.8% delta. Cinebench R23 multi-core shows 15416 versus 15292, also -0.8%, and R23 single-core shows 2176 versus 2158, also -0.8%.

These are small but repeatable advantages. Across six Cinebench tests, the i7-9800X never loses, and its lead never exceeds 0.9%. This suggests a stable, architectural advantage in Cinebench workloads, likely related to the larger L2 cache and higher memory bandwidth of the Skylake-X design.

The Geekbench results are a different story entirely. In Geekbench multi-core, the i9-9900KF scores 8970 against the i7-9800X's 7488, a commanding 19.8% lead. In Geekbench single-core, the i9-9900KF scores 1706 versus 1398, a 22% lead. These are the largest deltas in the entire head-to-head set, and they invert the Cinebench narrative completely.

The divergence between Cinebench and Geekbench is instructive. Cinebench R15, R20, and R23 are rendering workloads that scale with sustained multi-threaded throughput and memory bandwidth, favoring the i7-9800X. Geekbench, on the other hand, includes a mix of integer, floating-point, and memory tests that often reward higher clock speeds and lower latency, favoring the i9-9900KF's 5.00 GHz boost clock.

The average benchmark scores reflect this split. The i9-9900KF averages 4652, which is 0.3% behind the Intel Core i9-10900F and 0.7% behind the Intel Core i9-11900T, but 0.8% ahead of the Intel Core i9-10900 and 1.2% ahead of the Intel Core i9-10900E. The i7-9800X averages 4455, which is 0.3% behind the AMD Ryzen 5 PRO 5650GE, 1% ahead of the AMD Ryzen 7 PRO 4750GE, and 1.3% behind the Intel Core i7-12700TE and Intel Core i5-1250P.

In the final tally, the i7-9800X wins 6 benchmarks and the i9-9900KF wins 2. But the two i9-9900KF wins are by margins of 19.8% and 22%, while the i7-9800X wins are all under 1%. The i9-9900KF is the stronger all-rounder in the database's overall scoring, with a higher average benchmark score, while the i7-9800X is a specialist that excels in Cinebench-style rendering work.