Doom

The AMD Ryzen 5 8400F paired with the AMD Radeon RX 7900 XT delivers a formidable 1080p experience in Doom, but the data reveals a clear shift in bottleneck behavior as resolution increases. At 1080p, the combo achieves 335.4 FPS on Low settings, yet this drops to 202.4 FPS on Ultra, a substantial 39.7% reduction. This scaling pattern indicates that at lower resolutions, the CPU’s single-thread performance is the primary limiter, preventing the GPU from reaching its full potential. However, the gap between settings narrows at 4K, where the Ultra preset yields 68.8 FPS and Low produces 117.1 FPS, a 41.2% difference. This suggests that at 4K, the GPU’s shading and memory throughput become the dominant constraint, with the CPU’s role diminishing.

Resolution Scaling

The measured FPS data shows a predictable decline as resolution climbs, but the rate of that decline is telling. Moving from 1080p to 1440p at High settings, the average FPS falls from 250.2 to 158.7, a 36.6% drop. The transition from 1440p to 4K at the same settings is less severe in percentage terms, with a 44.0% reduction from 158.7 to 88.8 FPS. This pattern—where the largest absolute hit occurs between 1080p and 1440p—indicates that the CPU can still feed the GPU adequately at 1440p, but the GPU’s raw fill rate is increasingly taxed. At 4K Ultra, the 68.8 FPS result is notably lower than the 88.8 FPS at High, underscoring that the RX 7900 XT’s 20 GB of VRAM and 800.0 GB/s bandwidth are sufficient, but the shading workload from Ultra settings pushes the Navi 31 chip to its limits.

The 1080p Low result of 335.4 FPS versus the 4K Low result of 117.1 FPS highlights a 65.1% performance reduction. This is a classic signature of a GPU-bound scenario at 4K, where the CPU’s 4.70 GHz boost clock and 6 cores are less relevant than the GPU’s pixel rate of 459.6 GPixel/s. Conversely, at 1080p, the gap between Low and Ultra (335.4 vs 202.4 FPS) is only 39.7%, which is relatively small for a game with Doom’s visual complexity, implying that frame rates are being capped by the CPU’s ability to issue draw calls rather than the GPU’s rendering speed. Benchmark results indicate that users targeting 4K should prioritize GPU headroom, while 1080p users are more likely to see CPU-bound behavior.

Settings Recommendations

For the best experience per the measured rows, the High preset emerges as the optimal balance across all resolutions. At 1080p, High delivers 250.2 FPS, which is 18.2% lower than Low but 23.6% higher than Ultra. The visual fidelity gain from High over Medium is modest (250.2 vs 295.1 FPS), but the drop from Medium to High is only 15.2%, making High a stable choice. At 1440p, High produces 158.7 FPS, comfortably above the 131 FPS of Ultra, and the difference between Medium and High is 17.9%. This makes High the sweet spot for maintaining high refresh rates without sacrificing too much image quality.

At 4K, High’s 88.8 FPS is the only preset that stays above 90% of the Low preset’s 117.1 FPS, while Ultra falls to 68.8 FPS. The data suggests that Ultra is only advisable for users with 60 Hz displays, as it provides a 22.5% reduction from High. Medium at 4K (102.2 FPS) is closer to High than to Ultra, but High’s additional visual features justify the 13.1% performance cost. For competitive play, Low at 1440p (221.8 FPS) offers a significant 28.4% advantage over High, but for most users, High at 1440p provides an excellent 158.7 FPS experience. The verdict is clear: High is the recommended preset for this combo, with Low reserved for maximum frame rates and Ultra only for immersive single-player sessions.

CPU Role

The AMD Ryzen 5 8400F is a 6-core, 12-thread processor based on the Zen 4 architecture, clocked at 4.20 GHz base and 4.70 GHz boost. Its benchmark scores reveal a strong single-thread capability, with a Cinebench R23 single-core score of 2943 and a 3DMark single-thread score of 951. These numbers are critical for Doom, which is known for its efficient multi-threading but still relies heavily on a few main threads for game logic. The CPU’s PassMark single-thread score of 3684 places it in the 82nd percentile of all CPUs, indicating solid performance for this workload.

In the measured FPS data, the CPU’s influence is most apparent at 1080p Low, where the 335.4 FPS result is likely near the engine’s frame rate ceiling for this processor. The jump from Low to Medium at 1080p (295.1 FPS) is only 12.0%, suggesting that the CPU is not the limiting factor at Medium. However, the difference between Medium and High at 1080p (295.1 vs 250.2 FPS) is 15.2%, which is larger than the 1440p equivalent (193.3 vs 158.7 FPS, a 17.9% drop). This indicates that at 1080p, the CPU’s 16 MB of shared L3 cache and 83.2 GB/s memory bandwidth are sufficient to feed the GPU, but the GPU’s shading units become the bottleneck at higher settings. The 3DMark 16-thread score of 6091 versus the max-thread score of 6165 shows that the CPU scales well with threads, but Doom’s frame rates do not increase proportionally with core count beyond 6 cores, as evidenced by the 1080p results.

FAQ

Q: What is the highest average FPS achievable with this combo at 1080p?

A: The highest measured average is 335.4 FPS at 1080p with the Low preset. The High preset yields 250.2 FPS, and Ultra drops to 202.4 FPS.

Q: How does the combo perform at 4K Ultra settings?

A: At 3840x2160 with Ultra settings, the average FPS is 68.8. This is the lowest result in the measured data, indicating that Ultra at 4K is demanding for the RX 7900 XT.

Q: Is the CPU or GPU the bottleneck at 1440p High?

A: At 1440p High, the average FPS is 158.7. Comparing this to the 1080p High result of 250.2 FPS, the 36.6% drop suggests the GPU is becoming the primary limiter, as the CPU’s 4.70 GHz boost clock is less stressed at higher resolutions.

Q: What is the frame rate difference between Medium and High at 4K?

A: At 4K, Medium averages 102.2 FPS while High averages 88.8 FPS, a difference of 13.1%. This is a smaller relative gap than at 1080p, where Medium (295.1) and High (250.2) differ by 15.2%.

Q: Does the combo’s CPU performance percentile affect Doom’s frame rates?

A: The Ryzen 5 8400F has a percentile vs all CPUs of 82, which is high. This correlates with the strong 1080p results, but the GPU’s 82nd percentile vs all GPUs is equally important, as the RX 7900 XT’s 51.48 TFLOPS FP32 performance drives the 4K results.

Q: What is the most significant frame rate drop between settings?

A: The largest drop is from Low to Ultra at 4K, where FPS falls from 117.1 to 68.8, a 41.2% reduction. This is larger than the 1080p Low-to-Ultra drop of 39.7%.

GPU Role

The AMD Radeon RX 7900 XT is a behemoth with 5376 shading units, 336 TMUs, and 192 ROPs, built on the RDNA 3.0 architecture. Its 20 GB of GDDR6 memory on a 320-bit bus provides 800.0 GB/s of bandwidth, which is crucial for high-resolution textures. The GPU’s boost clock of 2394 MHz and game clock of 2025 MHz deliver a pixel rate of 459.6 GPixel/s and a texture rate of 804.4 GTexel/s. These specifications are directly reflected in the measured FPS, particularly at 4K where the GPU’s raw compute power is the deciding factor.

At 4K Ultra, the 68.8 FPS result is the lowest in the dataset, which aligns with the GPU’s 82nd percentile ranking among all GPUs. The gap between 4K High (88.8 FPS) and 4K Medium (102.2 FPS) is 13.1%, showing that the GPU’s shading units are sensitive to preset changes. The RX 7900 XT’s PassMark G3D score of 29009 and 3DMark Steel Nomad DX12 score of 5623 corroborate its strong performance. Notably, the GPU’s nearest rival, the NVIDIA GeForce RTX 5080 Mobile, has a deltaPct of 0, indicating near-identical average benchmark scores, but the mobile variant’s power constraints would likely produce different in-game results. The 4K Low result of 117.1 FPS demonstrates that the GPU can handle high frame rates at 4K when visual effects are reduced, but the 20 GB VRAM is never fully taxed, as even Ultra settings do not exceed its capacity.

Measured FPS Breakdown

At 1920x1080, the combo delivers exceptional performance. Low settings produce 335.4 FPS, Medium 295.1 FPS, High 250.2 FPS, and Ultra 202.4 FPS. The progression from Low to Ultra shows a consistent 15-18% reduction per step, with the largest single drop being from Medium to High (15.2%). This resolution demonstrates the CPU’s strength, as the 6-core processor can maintain high frame rates even at Low.

At 2560x1440, the results are 221.8 FPS (Low), 193.3 FPS (Medium), 158.7 FPS (High), and 131 FPS (Ultra). The drop from Low to Ultra is 40.9%, which is slightly larger than at 1080p, indicating a growing GPU influence. The difference between High and Ultra is 17.5%, suggesting that Ultra settings at 1440p are less efficient than High.

At 3840x2160, the results are 117.1 FPS (Low), 102.2 FPS (Medium), 88.8 FPS (High), and 68.8 FPS (Ultra). The drop from Low to Ultra is 41.2%, the largest of any resolution. This demonstrates that the GPU is the clear bottleneck at 4K, with the RX 7900 XT’s 51.48 TFLOPS being the limiting factor. The 4K High result of 88.8 FPS is still playable, but the 4K Ultra result of 68.8 FPS is the only measurement below 70 FPS across the entire dataset.

How This Combo Ranks

The combo ranks 373rd out of 1681 tested combinations in Doom, placing it in the top 22.2% of all configs. This ranking is impressive given the CPU’s mid-range positioning, but it is the GPU that boosts the overall score. The Ryzen 5 8400F’s nearest rivals include the AMD Ryzen 7 2700X (deltaPct 0), AMD Ryzen AI 5 PRO 340 (deltaPct -0.1), and AMD EPYC 9474F (deltaPct -0.2), showing that the CPU’s performance is tightly clustered with these parts. However, the RX 7900 XT’s nearest rivals, such as the NVIDIA GeForce RTX 5080 Mobile (deltaPct 0) and NVIDIA CMP 70HX (deltaPct 0.3), are all within 0.6% in average benchmark score, indicating that the GPU is a top-tier performer.

The 373rd rank out of 1681 combos suggests that while the GPU is exceptional, the CPU holds the combo back slightly. In a game like Doom, which rewards high single-thread performance, the CPU’s 3DMark single-thread score of 951 is adequate but not elite. The measured FPS at 1080p Low (335.4 FPS) is likely near the CPU’s ceiling, whereas a higher-end CPU could push that number further. At 4K, the combo’s rank would be significantly higher, as the GPU’s 800.0 GB/s bandwidth and 20 GB memory become the dominant factors. Overall, the data indicates that this combo is well-balanced for 1440p gaming, offering 158.7 FPS at High, while 1080p users will see CPU-limited performance and 4K users will be GPU-limited.