Fortnite

Fortnite on the Intel Core i5-9400 and NVIDIA GeForce RTX 5090 pairing presents a study in how a high-end GPU can be constrained by a mid-range processor from an earlier generation. The measured data reveals a system that delivers playable frame rates across all tested configurations, but the scaling patterns expose a CPU bottleneck at lower resolutions and a GPU workload that becomes increasingly dominant as resolution climbs. This analysis walks through the resolution scaling, the combo’s standing among tested configurations, the GPU’s specific role, and the settings that produce the best experience.

Resolution Scaling

The FPS drop from 1080p to 4K is substantial, but the magnitude varies dramatically by settings preset. At Low settings, the average frame rate falls from 290.4 FPS at 1920x1080 to 166.5 FPS at 3840x2160 — a reduction of 123.9 FPS, or roughly 42.7% of the 1080p figure. This steep decline indicates that even at Low settings, the GPU is doing significantly more work at 4K, while the CPU has more headroom to feed frames at lower resolutions. The gap between 1080p and 1440p at Low is narrower, with the average dropping from 290.4 to 251.6 FPS, which still shows a 38.8 FPS hit.

At Medium settings, the same pattern holds. The 1080p average is 256.4 FPS, falling to 218.7 FPS at 1440p and then 118.8 FPS at 4K. The drop from 1440p to 4K is 99.9 FPS, which is larger than the 37.7 FPS drop from 1080p to 1440p. This accelerating decline suggests that 4K resolution is pushing the RTX 5090 toward its limits at Medium settings, while the CPU remains capable of keeping up at the lower resolutions. The High preset shows a similar trend: 229.7 FPS at 1080p, 173.3 FPS at 1440p, and 94.1 FPS at 4K. The 4K figure is barely above half of the 1080p number, confirming that the GPU becomes the primary limiting factor at the highest resolution.

Ultra settings produce the most dramatic scaling. At 1080p, the average is 175.8 FPS, which drops to 115.6 FPS at 1440p and then plummets to 60.7 FPS at 4K. The 4K Ultra result is only about 34.5% of the 1080p Ultra figure, indicating that the combination of maximum graphics quality and 4K resolution creates an exceptionally heavy GPU workload. Across all presets, the 1080p to 4K scaling shows that the RTX 5090’s raw power is less able to compensate for the CPU’s limitations at lower resolutions, where the i5-9400’s six cores and six threads become the bottleneck.

How This Combo Ranks

The combo ranks 113th out of 1,564 tested combinations in Fortnite, placing it in the top 7.2% of all pairings in the database. This percentile position reflects the strong GPU contribution, but the rank also indicates that many other CPU-GPU pairings deliver higher average frame rates. The i5-9400 sits in the 50th percentile among all CPUs, with an average benchmark score of 2,305, while the RTX 5090 ranks in the 94th percentile among all GPUs with an average score of 84,306. The disparity between these percentiles explains why the combo does not rank higher — the GPU is near the top of its class, but the CPU is squarely mid-pack.

The CPU’s nearest rivals in the benchmark database illustrate its positioning. The Intel Core i3-10305 has an average score of 2,300, which is 0.2% lower than the i5-9400. The Intel Core i3-1125G4 matches that 0.2% delta with a score of 2,299. The Intel Xeon E-2134 is 0.4% behind at 2,295, while the Intel Core i7-8809G is 0.6% ahead at 2,319. These tight deltas show that the i5-9400 is clustered with several other mid-range processors, none of which offer a meaningful performance advantage. This CPU performance level, when paired with a top-tier GPU, yields the observed 113th rank — respectable but not elite.

GPU Role

The RTX 5090 is a Blackwell 2.0 architecture GPU built on a 5 nm process at TSMC, with a die size of 750 mm² and 92,200 million transistors. Its memory subsystem is substantial: 32 GB of GDDR7 on a 512-bit bus, providing 1.79 TB/s of bandwidth. The memory clock runs at 1750 MHz, translating to 28 Gbps effective. These specifications support the GPU’s ability to handle 4K workloads, as evidenced by the measured frame rates, but the data shows that the GPU is not always the bottleneck.

The GPU’s base clock is 2017 MHz with a boost clock of 2407 MHz. It has 21,760 shading units, 680 texture mapping units, and 176 raster output units, along with 170 ray tracing cores and 680 tensor cores. The pixel rate is 423.6 GPixel/s, and the texture rate is 1,636.8 GTexel/s. The FP32 performance is 104.8 TFLOPS, with the same figure for FP16 (1:1). These numbers place the RTX 5090 in the 94th percentile among all GPUs, with an average benchmark score of 84,306. Its nearest rival, the RTX 5090 D, scores 84,241, a 0.1% delta, while the RTX 5050 Mobile is 0.2% behind at 84,171. The AMD Radeon PRO W6600 trails by 1.3% at 83,209, and the NVIDIA CMP 40HX leads by 1.6% at 85,637.

In Fortnite, the GPU’s role becomes more prominent at higher resolutions. At 4K Ultra, the 60.7 FPS average suggests the GPU is the limiting component, as the CPU’s frame generation capability is less likely to be the constraint at such a heavy workload. Conversely, at 1080p Low, the 290.4 FPS average is likely capped by the CPU, since the GPU could theoretically deliver more frames if the processor could feed it faster. The data indicates that the RTX 5090 has ample headroom at lower resolutions, but the i5-9400 cannot fully exploit it.

Settings Recommendations

The measured rows provide a clear picture of which preset offers the best experience. At 4K, the Medium preset delivers 118.8 FPS, which is notably smoother than High’s 94.1 FPS and far better than Ultra’s 60.7 FPS. The Low preset at 4K reaches 166.5 FPS, but the visual quality trade-off is significant. For competitive play at 4K, Medium appears to be the sweet spot, offering a playable frame rate without dropping to the lowest visual settings.

At 1440p, the Medium preset achieves 218.7 FPS, while High is at 173.3 FPS and Ultra at 115.6 FPS. The Low preset hits 251.6 FPS, but Medium provides a better balance of visual fidelity and performance. For 1080p, Medium delivers 256.4 FPS, which is more than sufficient for any display refresh rate, while High reaches 229.7 FPS and Ultra remains above 175.8 FPS. The data suggests that Medium settings across all resolutions provide the most consistent experience, with frame rates that never drop below 118.8 FPS even at 4K.

Measured FPS Breakdown

At 1920x1080, the measured average frame rates are as follows: Low settings produce 290.4 FPS, Medium settings yield 256.4 FPS, High settings deliver 229.7 FPS, and Ultra settings reach 175.8 FPS. The spread from Low to Ultra is 114.6 FPS, showing that the preset choice has a substantial impact at this resolution. The 1080p results are the highest across all resolutions, confirming that the CPU is the limiting factor here.

At 2560x1440, the averages are 251.6 FPS for Low, 218.7 FPS for Medium, 173.3 FPS for High, and 115.6 FPS for Ultra. The drop from 1080p to 1440p ranges from 38.8 FPS at Low to 60.2 FPS at Ultra, indicating that the GPU’s workload increases significantly at this resolution. The 1440p Medium result of 218.7 FPS is particularly notable, as it remains above the 1080p High figure of 229.7 FPS by a smaller margin.

At 3840x2160, the averages are 166.5 FPS for Low, 118.8 FPS for Medium, 94.1 FPS for High, and 60.7 FPS for Ultra. The 4K results show the largest drop from 1440p, with the Low preset falling by 85.1 FPS and Ultra falling by 54.9 FPS. The 4K Ultra figure of 60.7 FPS is the lowest measured value across the entire dataset, emphasizing the extreme GPU load at maximum settings and resolution.

FAQ

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

A: The highest measured average at 1920x1080 is 290.4 FPS, achieved with Low settings.

Q: How does the 4K Ultra preset compare to the 1080p Ultra preset?

A: The 4K Ultra average is 60.7 FPS, while the 1080p Ultra average is 175.8 FPS, representing a drop of 115.1 FPS.

Q: What rank does this combo hold among all tested combinations in Fortnite?

A: The combo ranks 113th out of 1,564 tested combinations.

Q: Which settings preset at 4K provides the best balance of visual quality and frame rate?

A: The Medium preset at 3840x2160 delivers 118.8 FPS, which is higher than High’s 94.1 FPS and Ultra’s 60.7 FPS, while offering better visuals than Low’s 166.5 FPS.

Q: What is the CPU’s percentile ranking among all CPUs?

A: The Intel Core i5-9400 sits in the 50th percentile, with an average benchmark score of 2,305.

Q: What is the GPU’s memory bandwidth and size?

A: The RTX 5090 has 32 GB of GDDR7 memory on a 512-bit bus, providing 1.79 TB/s of bandwidth.