Doom

The Intel Core i5-9400 paired with the AMD Radeon RX 7900 XTX delivers a benchmark performance ranking of 398 out of 1,681 tested combinations in Doom. This places the combo in the top 24% of all tested systems, a strong result that underscores the substantial graphics horsepower available in this configuration. The ranking indicates that while the CPU is not a top-tier part, the overall system is capable of achieving frame rates that are well above the median for this title, making it a viable setup for high-refresh-rate displays even before considering the specific FPS measurements.

How This Combo Ranks

The combo's rank of 398 out of 1,681 places it firmly in the upper quartile of tested systems. This position is driven almost entirely by the GPU, which sits in the 85th percentile of all tested graphics cards. In contrast, the CPU sits at the 50th percentile of all tested processors, indicating a significant imbalance in capability. The data suggests that the system's performance in Doom is not constrained by the processor at most settings, but the gap between the two components' relative standings is a critical factor. The high overall rank confirms the GPU's ability to push frame rates high enough to overcome the CPU's more modest standing, though the specific bottlenecks become apparent when analyzing scaling across resolutions.

GPU Role

The AMD Radeon RX 7900 XTX is the dominant component in this configuration, featuring a massive 24 GB of GDDR6 memory on a 384-bit bus, yielding a bandwidth of 960.0 GB/s. This memory subsystem is critical for high-resolution textures and ensures that the GPU does not run out of frame buffer space at any tested setting. The GPU's architecture, RDNA 3.0 on a 5 nm process, operates with a base clock of 1929 MHz and a boost clock of 2498 MHz. The game clock is listed at 2365 MHz, which is a more realistic sustained frequency during gaming loads. With 6,144 shading units and 192 ROPs, the card is built for raw throughput, which is reflected in its 3DMark Steel Nomad score of 6,841. In Doom, a title known for its scalability, this GPU provides the vast majority of the computational muscle, allowing for exceptionally high frame rates even at 4K. The GPU's average benchmark score of 44,019 places it just 0.8% behind the NVIDIA GeForce RTX 4090 Mobile and 2% behind the NVIDIA GeForce RTX 4070 Ti, highlighting its position near the top of the performance hierarchy.

CPU Role

The Intel Core i5-9400 provides six cores and six threads, operating at a base clock of 2.90 GHz and a boost clock of 4.10 GHz. This Coffee Lake processor lacks hyper-threading, which can be a limitation in modern, heavily threaded titles, but Doom's id Tech engine is known for scaling well with fewer, faster cores. The CPU's L3 cache is 9 MB shared, and it supports DDR4 memory on a dual-channel bus, which is standard for its platform. Its average benchmark score of 2,305 puts it statistically on par with its nearest rivals, such as the Intel Core i3-10305 (0.2% faster) and the Intel Core i7-8809G (0.6% slower). In the context of this game, the CPU's role is to feed the GPU with draw calls and physics data. At 1080p, the CPU becomes the limiting factor, as seen in the FPS data, but its six physical cores are sufficient to maintain playable and often very high frame rates. The 4.10 GHz boost clock is essential for maintaining minimum frame times when the GPU is not the bottleneck.

Measured FPS Breakdown

The measured FPS data shows a clear hierarchy based on resolution and settings. At 1080p, the lowest tested resolution, the combo produces exceptional results. With Low settings, the average FPS is 255.4, which drops slightly to 244.6 at Medium and 229.0 at High. Even at Ultra settings, the average FPS remains a very high 209.9. The spread between Low and Ultra is only 45.5 FPS, indicating that the CPU is starting to limit performance, as the GPU has enough headroom to handle the increased graphical load without a proportional drop in frame rate. Moving to 1440p, the frame rates remain high. Low settings produce 217.8 FPS, Medium yields 204.1 FPS, and High achieves 170.5 FPS. Ultra settings at 1440p bring the average down to 142.9 FPS. The delta between Low and Ultra at 1440p is 74.9 FPS, showing that the GPU is now taking on more work and the scaling is more pronounced. At 4K, the resolution where the GPU is fully stressed, the trend continues. Medium settings achieve 112.6 FPS, High settings hit 93.7 FPS, and Ultra settings drop to 80.0 FPS. The Low setting at 4K still manages a robust 126.4 FPS, demonstrating that the RX 7900 XTX has enough memory bandwidth and compute power to handle the resolution even with reduced graphical features.

Resolution Scaling

The scaling from 1080p to 4K reveals the relationship between the CPU and GPU. At Low settings, the FPS drops from 255.4 at 1080p to 126.4 at 4K, a reduction of 50.5%. This significant drop indicates that the GPU is the primary bottleneck at 4K, as the lower graphical load at 1080p allows the CPU to push frame rates higher, but the GPU cannot maintain that pace when pixel count quadruples. The scaling is less steep at Ultra settings, where the FPS drops from 209.9 to 80.0, a 61.9% reduction. This larger percentage drop at Ultra suggests that even at 1080p, the CPU is not entirely preventing the GPU from working harder, but the increased shading and texture work at Ultra scales more aggressively with resolution. The data shows that at 1080p, the CPU is the limiting component, as evidenced by the relatively small FPS delta between Low and Ultra (45.5 FPS). At 4K, the GPU becomes the clear limiting factor, with the FPS delta between Low and Ultra growing to 46.4 FPS, but the absolute values are lower, confirming the GPU's workload is the constraint. The 4K Ultra result of 80.0 FPS is still very playable and indicates that this combination is capable of high-fidelity gaming at the highest resolution, while the 1080p Low result of 255.4 FPS shows the CPU's ceiling in this engine.