Microsoft Flight Simulator

Microsoft Flight Simulator presents one of the most demanding workloads in PC gaming, and the combination of the Intel Core i5-13400F and NVIDIA GeForce RTX 4090 delivers a fascinating study in system balance. The measured frame rates across resolutions and settings reveal a configuration where the GPU’s immense power is frequently tempered by the CPU’s capabilities, particularly at lower resolutions. This analysis breaks down the performance data, focusing on where the bottleneck shifts and what that means for the overall experience.

Resolution Scaling

The performance scaling from 1080p to 4K clearly illustrates the shifting balance of load between the processor and graphics card. At 1080p with Low settings, the system achieves an average of 194.7 FPS, a figure that drops to 177.3 FPS at 1440p and further to 137.4 FPS at 4K. This progression shows that even at the lowest settings, the RTX 4090 is not fully saturated at 1080p; the 11.5% performance drop from 1080p to 1440p is relatively modest, suggesting the CPU is the primary limiter at these lower resolutions. The data points to a scenario where the i5-13400F’s 10 cores and 16 threads are working hard to feed the frame pipeline, preventing the GPU from reaching its full potential.

The scaling picture changes dramatically when moving to High settings. Here, the frame rate at 1080p is 139.4 FPS, while 1440p yields 112 FPS and 4K drops to 78.5 FPS. The performance gap between 1080p and 1440p is 19.6%, and between 1440p and 4K it is 29.9%. This steeper decline indicates that the GPU is becoming a more significant factor as resolution increases, but the absolute numbers still show a system that is heavily CPU-bound at 1080p. It is not until the jump to 4K that the RTX 4090’s rendering workload truly begins to dominate the equation, with the frame rate dropping by more than half compared to the 1080p Low result.

At Ultra settings, the trend continues, with 131.1 FPS at 1080p, 105.2 FPS at 1440p, and 78.5 FPS at 4K. Interesting to note is that the 4K Ultra and 4K High results are identical at 78.5 FPS, which strongly suggests that the CPU has become the definitive bottleneck at this resolution and settings combination. The GPU is capable of rendering more frames, but the processor cannot issue draw calls fast enough. The data indicates that for this specific pairing, the RTX 4090’s full potential is only realized at 4K, where its raw power is finally the limiting factor. The overall pattern shows a system where 1080p and 1440p performance is constrained by the CPU, while 4K performance is a more balanced mix, though still capped by the processor in the most demanding settings.

CPU Role

The Intel Core i5-13400F is a 10-core, 16-thread processor based on the Raptor Lake architecture, with a base clock of 2.50 GHz and a boost clock of 4.60 GHz. Its benchmark scores place it in the 82nd percentile of all CPUs, with an average benchmark score of 25236. This places it in a tight cluster with rivals like the AMD Ryzen 5 5600X3D, which scores 25365 (a 0.5% difference), and the Intel Core i7-13620H, which scores 25201 (a 0.1% difference). These results indicate that the i5-13400F is a highly capable mid-range processor, but it is not a flagship part.

In Microsoft Flight Simulator, the CPU’s role is critical for simulation logic, physics, and draw call processing. The measured FPS data reveals that at 1080p Low, the system hits 194.7 FPS, but this is far below what the RTX 4090 could theoretically produce. The single-thread performance, as shown by a 3DMark single-thread score of 960, is strong, but the game’s demands on multiple cores are evident. The 3DMark 16-thread score of 7314 and the Cinebench R23 multi-core score of 21279 show solid multi-threaded capability, yet the frame rates at lower resolutions suggest that the processor’s maximum throughput is the limiting factor.

The identical 78.5 FPS results at 4K High and 4K Ultra are a clear indicator of a CPU ceiling. No matter how much graphical detail is added, the processor cannot push the frame rate higher. This is a classic sign of a CPU bottleneck, where the game’s main thread is saturated. The data suggests that while the i5-13400F is a good match for many games, pairing it with the fastest consumer GPU on the market will leave performance on the table in CPU-intensive titles like this one. The processor’s 20 MB of shared L3 cache and 1.25 MB per-core L2 cache help, but the fundamental throughput limit is reached. The benchmark results show it is only 0.5% slower than the AMD EPYC 9474F, which is a server-class chip, but that comparison is for synthetic workloads, not this specific game’s engine.

GPU Role

The NVIDIA GeForce RTX 4090 is a behemoth, built on the Ada Lovelace architecture with a 5 nm process. It features 16,384 shading units, 512 tensor cores, and 128 RT cores, with a boost clock of 2520 MHz. The 24 GB of GDDR6X memory on a 384-bit bus provides a massive 1.01 TB/s of bandwidth. It scores in the 91st percentile of all GPUs, with an average benchmark score of 66473. Its nearest rivals in the database are professional workstation cards like the NVIDIA Tesla T4 (66733 score, 0.4% faster) and the AMD Radeon Pro Vega 56 (67097 score, 0.9% faster), which underscores its position as a top-tier consumer part.

The GPU’s role in Flight Simulator is to render the complex scenery, terrain, and aircraft models. The data shows that the RTX 4090 is rarely the limiting factor at 1080p and 1440p. For instance, at 1440p Medium, the system produces 146.2 FPS, while at 1440p Low it hits 177.3 FPS. The GPU is capable of handling these resolutions with ease. It is only at 4K that the graphics card starts to show its workload. The jump from 4K Low (137.4 FPS) to 4K Medium (103.6 FPS) is a 24.6% drop, showing the cost of increased detail. The high memory bandwidth is crucial for streaming textures at this resolution, and the 24 GB frame buffer ensures there are no capacity issues.

However, even at 4K, the GPU’s power is not fully utilized in all settings. The fact that High and Ultra both produce 78.5 FPS indicates that the rendering workload is not the primary constraint at those settings. The RTX 4090 is effectively waiting for the CPU. This is not a fault of the GPU; it is a consequence of pairing it with a mid-range processor. The pixel rate of 443.5 GPixel/s and texture rate of 1,290.2 GTexel/s are more than sufficient for the task. The data suggests that the RTX 4090 is a future-proof component that will handle any resolution, but its full potential is gated by the CPU in this specific configuration.

FAQ

Q: Why is the 4K High and 4K Ultra frame rate identical at 78.5 FPS?

A: The identical frame rates indicate a CPU bottleneck. The Intel Core i5-13400F cannot issue rendering commands fast enough to keep the RTX 4090 fully occupied, regardless of the added graphical detail from Ultra settings.

Q: Is the RTX 4090 being held back by the i5-13400F?

A: Yes, at 1080p and 1440p, the data shows the system is heavily CPU-limited. For example, at 1080p Low, the frame rate is 194.7 FPS, which is far below the GPU’s capability. The CPU’s 82nd percentile ranking among all CPUs, while strong, is not sufficient to unlock the full potential of a GPU in the 91st percentile.

Q: What is the best resolution for this combination to avoid a CPU bottleneck?

A: Based on the data, 4K is the resolution where the GPU becomes the more dominant factor. The frame rates at 4K (137.4 FPS Low, 103.6 FPS Medium, 78.5 FPS High/Ultra) show a more significant performance drop with increased settings, indicating the GPU is handling more of the workload.

Q: How does the i5-13400F compare to its nearest rival, the AMD Ryzen 5 5600X3D?

A: The average benchmark scores are very close. The i5-13400F scores 25236, while the Ryzen 5 5600X3D scores 25365, making the AMD part 0.5% faster in synthetic tests. This difference is negligible for real-world gaming performance.

Q: Does the RTX 4090’s 24 GB of VRAM provide any advantage in this game?

A: The large memory capacity and 1.01 TB/s bandwidth ensure that there are no texture loading issues at 4K. However, the frame rate data suggests that raw memory capacity is not the limiting factor, as the CPU bottleneck occurs before VRAM becomes an issue.

Q: Is the i5-13400F a good match for the RTX 4090?

A: The data indicates it is not an ideal match for maximum performance in CPU-intensive games like Microsoft Flight Simulator. While it delivers playable frame rates at all settings, the identical 78.5 FPS results at 4K High and Ultra show that the processor is the primary constraint.

Measured FPS Breakdown

The following table details the exact average frame rates measured for this configuration. All data points are from the benchmark database and represent the average FPS across the test run.

| Resolution | Settings | Average FPS |

| :--------- | :------- | :---------- |

| 3840x2160 | High | 78.5 |

| 3840x2160 | Low | 137.4 |

| 3840x2160 | Medium | 103.6 |

| 3840x2160 | Ultra | 78.5 |

| 2560x1440 | High | 112.0 |

| 2560x1440 | Low | 177.3 |

| 2560x1440 | Medium | 146.2 |

| 2560x1440 | Ultra | 105.2 |

| 1920x1080 | High | 139.4 |

| 1920x1080 | Low | 194.7 |

| 1920x1080 | Medium | 174.7 |

| 1920x1080 | Ultra | 131.1 |

The data reveals a consistent pattern: the lowest frame rates are always at Ultra settings, and the highest are at Low settings. The spread between Low and Ultra is most pronounced at 4K, where the difference is 58.9 FPS (from 137.4 down to 78.5). This spread narrows at 1440p to 72.1 FPS (from 177.3 down to 105.2) and at 1080p to 63.6 FPS (from 194.7 down to 131.1). The relatively consistent performance at Ultra settings across resolutions (131.1 FPS at 1080p, 105.2 FPS at 1440p, 78.5 FPS at 4K) shows the CPU’s limits, as the GPU’s workload increases, the frame rate drops, but not as steeply as the resolution change would suggest if it were purely GPU-bound. The system ranks 38th out of 1795 tested combinations for this game, placing it in the top 2% of all tested configurations, but the performance data shows that for this specific simulator, the processor is the weak link in the chain.