Roblox

Roblox is not a typical graphics stress test, and the measured results for this AMD Ryzen 9 8945HX + NVIDIA GeForce RTX 4090 combination confirm it. The data shows a system that is overwhelmingly GPU-bound at 4K but transitions to being heavily CPU-limited at 1080p, with frame rates that exceed what most displays can even show. This is a laptop-class CPU paired with a flagship desktop GPU, and the benchmark results reflect that unusual pairing across all measured settings.

Resolution Scaling

The scaling from 1080p to 4K is dramatic and reveals a classic bottleneck shift. At 1080p Low, the combo delivers 505 FPS average. Dropping to 1440p Low reduces that to 337 FPS, a 33% decline. Moving further to 4K Low yields 191 FPS, which is another 43% drop from 1440p. The pattern is consistent across all settings: the frame rate falls sharply as resolution climbs, which points directly at the GPU becoming the limiting factor at higher pixel counts.

Look at the High preset specifically. At 1920x1080, the average is 407 FPS. At 2560x1440, it falls to 271 FPS, a 33% reduction. At 3840x2160, it drops to 153 FPS, another 44% cut. These are large, predictable declines that track with the pixel count increase. The 4K-to-1440p ratio is roughly 0.56, and the 1440p-to-1080p ratio is roughly 0.67. This is not a linear scaling, but it is consistent with a GPU that is being fed progressively more work per frame.

The interesting part is what happens at Low settings. The 1080p Low result of 505 FPS is the highest measured value in the entire dataset. At 1440p Low, it drops to 337 FPS, and at 4K Low, it falls to 191 FPS. The gap between Low and Ultra at 1080p is 175 FPS (505 vs 330), but at 4K that gap shrinks to 67 FPS (191 vs 124). This compression at higher resolutions indicates that the GPU is the dominant constraint at 4K, while at 1080p the CPU is likely holding back even the Low preset from going higher.

The data also shows that the Medium preset at 4K has a min FPS of 148 and a max of 200, with an average of 174. At 1440p Medium, the min is 261 and the max is 353, averaging 307. At 1080p Medium, the min is 391 and the max is 529, averaging 460. These min/max ranges widen as resolution drops, which is typical of a system where the CPU starts to introduce frame time variance at lower resolutions. The 1080p Medium spread of 138 FPS (391 to 529) is much larger than the 4K Medium spread of 52 FPS (148 to 200), suggesting that CPU scheduling or physics updates are causing more pronounced frame pacing issues when the GPU is not the limiting factor.

How This Combo Ranks

The combo rank in Roblox is 628 out of 3010 tested combinations. That places it in the top 21% of all combos, which is strong but not elite. The CPU itself has a percentile rank of 95 against all CPUs, meaning it outperforms 95% of processors in general benchmarks. The GPU has a percentile rank of 88 against all GPUs. Yet in this specific game, the combo only manages the 628th spot. This discrepancy indicates that Roblox's engine does not scale perfectly with the extreme hardware on offer, or that the game's thread utilization pattern favors other configurations.

The CPU's nearest rivals in average benchmark score are the Intel Core Ultra 9 285HX at 76155 (0.1% higher), the AMD EPYC Embedded 8224P at 76492 (0.4% higher), the AMD Ryzen Threadripper PRO 9945WX at 76513 (0.4% higher), and the AMD Ryzen 9 9950X3D at 75779 (0.6% lower). The Ryzen 9 8945HX scores 76212 on average. These are all extremely close scores, within a 1% band. This suggests that in synthetic workloads, the 8945HX is effectively on par with those other top-tier chips. However, the 9950X3D, which has 3D V-Cache, scores slightly lower in the average benchmark yet may behave differently in Roblox, which is not captured in the rival data.

The GPU's nearest rivals are much weaker overall. The Intel Arc Pro A60 scores 60326 (0% difference), the AMD Radeon Pro Vega 48 scores 60140 (0.3% higher), the AMD Radeon Pro W6600M scores 61896 (2.5% higher), and the AMD Radeon PRO V710 scores 58657 (2.9% lower). The RTX 4090 scores 60347 on average. These are workstation and professional GPUs, not gaming parts, and their scores are remarkably close to the RTX 4090's average. This is an artifact of the benchmark suite used, not a reflection of gaming performance. In Roblox, the RTX 4090's 88th percentile ranking is far above those rivals, but the combo rank still lands at 628 because the CPU-GPU pairing may not be optimal for this specific game's engine.

Settings Recommendations

The measured data provides a clear hierarchy for settings at each resolution. At 4K, the Ultra preset delivers 124 FPS average, which is playable but not exceptional. Medium delivers 174 FPS, a 40% improvement over Ultra. Low delivers 191 FPS, another 10% gain over Medium. High sits in between at 153 FPS. For a smooth 4K experience, Medium is the sweet spot because it offers a significant frame rate boost over High and Ultra while maintaining better visual quality than Low. The min FPS of 148 at 4K Medium is also above the 144 Hz refresh rate that many 4K monitors use, so it should avoid most visible stutters.

At 1440p, the story changes. High delivers 271 FPS, Medium delivers 307 FPS, and Low delivers 337 FPS. Ultra drops to 220 FPS. The gap between Low and High is 66 FPS, which is noticeable but not transformative. Since most 1440p gaming monitors top out at 144 Hz or 165 Hz, even the Ultra preset at 220 FPS is far beyond what the display can show. In that context, running Ultra at 1440p makes sense if the user wants maximum visual quality, because the frame rate is still far above any typical refresh rate cap. However, if the display supports 240 Hz or higher, then Medium at 307 FPS is the better choice to push closer to that limit.

At 1080p, the situation is entirely GPU-light and CPU-heavy. Low hits 505 FPS, Medium hits 460 FPS, High hits 407 FPS, and Ultra hits 330 FPS. All of these are well above 300 FPS, which exceeds even the fastest 360 Hz esports panels. The recommendation here is to use Ultra, because the visual quality gain costs only 175 FPS compared to Low, and the absolute frame rate is still enormous. There is no scenario in which 1080p Low is preferable to 1080p Ultra, given that both are far beyond display capabilities. The only caveat is that the CPU may cause frame time spikes, as evidenced by the 1080p Medium min of 391 FPS, which is still extremely high.

Measured FPS Breakdown

The dataset includes 12 measured configurations: four settings (Low, Medium, High, Ultra) at three resolutions. Starting at 1920x1080, the Low preset averages 505 FPS. Moving to Medium, the average drops to 460 FPS, with a minimum of 391 and a maximum of 529. High averages 407 FPS. Ultra averages 330 FPS. The progression from Low to Ultra is not linear: the drop from Low to Medium is 45 FPS, from Medium to High is 53 FPS, and from High to Ultra is 77 FPS. The largest penalty comes from the High-to-Ultra transition, which suggests that Ultra settings include some expensive effects.

At 2560x1440, Low averages 337 FPS. Medium averages 307 FPS, with a minimum of 261 and a maximum of 353. High averages 271 FPS. Ultra averages 220 FPS. The delta between Low and Ultra is 117 FPS, which is a smaller absolute gap than at 1080p (175 FPS) but a similar percentage reduction (roughly 35% drop from Low to Ultra). The Medium preset's min of 261 FPS is still very high, meaning that even with frame time variance, the system rarely drops below 260 FPS at this resolution.

At 3840x2160, Low averages 191 FPS. Medium averages 174 FPS, with a minimum of 148 and a maximum of 200. High averages 153 FPS. Ultra averages 124 FPS. The drop from Low to Ultra is 67 FPS, which is the smallest absolute gap across all resolutions. This confirms that at 4K, the GPU is the bottleneck, and the settings have less relative impact because the pixel workload dominates. The Medium preset's min of 148 FPS is notable because it is the lowest minimum in the entire dataset, indicating that 4K Medium can occasionally dip below the 144 Hz line.

Comparing across resolutions at the same setting, the scaling is consistent. For Low, 1080p to 1440p is a 33% drop (505 to 337), and 1440p to 4K is a 43% drop (337 to 191). For Medium, the drops are 33% (460 to 307) and 43% (307 to 174). For High, they are 33% (407 to 271) and 44% (271 to 153). For Ultra, they are 33% (330 to 220) and 44% (220 to 124). This uniformity suggests that the frame rate scaling is driven almost entirely by pixel count, with no settings-based interaction effect.

GPU Role

The NVIDIA GeForce RTX 4090 in this combo is a behemoth with 24 GB of GDDR6X memory on a 384-bit bus, delivering 1.01 TB/s of bandwidth. Its base clock is 2235 MHz and boost clock is 2520 MHz. The GPU has 16384 shading units, 512 TMUs, and 176 ROPs. It also features 128 RT cores and 512 tensor cores. The FP32 performance is 82.58 TFLOPS. These specs are far beyond what any game, let alone Roblox, can fully utilize, but the measured results show that at 4K, the GPU is still the limiting factor.

At 4K Ultra, the combo produces 124 FPS. That is a solid result for a demanding setting, but it is not the 500+ FPS seen at 1080p Low. The GPU's memory bandwidth of 1.01 TB/s is likely sufficient for Roblox's textures, but the sheer pixel fill rate required at 3840x2160 is what drives the frame rate down. The pixel rate of 443.5 GPixel/s and texture rate of 1,290.2 GTexel/s are enormous, yet Roblox's engine still manages to be GPU-bound at 4K because of the total work per frame.

The GPU's average benchmark score is 60347, with a percentile rank of 88. Its nearest rivals in the benchmark database are all professional GPUs, with the Intel Arc Pro A60 matching at 0% delta and the AMD Radeon Pro W6600M being 2.5% faster in that specific average. This is misleading because those GPUs have nowhere near the gaming performance of the RTX 4090. In Roblox, the RTX 4090's advantage is clear from the FPS numbers, but the combo rank of 628 shows that other factors, such as CPU behavior, also matter.

The GPU's 24 GB VRAM is more than enough for Roblox, which is a game known for its low asset complexity. The GDDR6X memory at 21 Gbps effective is overkill. The data does not show any VRAM limitation, as the frame rates scale smoothly with resolution. The GPU's role is purely about rasterization speed at high pixel counts, and the results confirm that it handles 4K well but not at the stratospheric frame rates seen at lower resolutions.

CPU Role

The AMD Ryzen 9 8945HX is a 16-core, 32-thread mobile processor based on Zen 4 architecture, codenamed Dragon Range. It has a base clock of 2.50 GHz and a boost clock of 5.40 GHz. The L3 cache is 64 MB, and it supports DDR5 memory in dual-channel mode with 83.2 GB/s bandwidth. The CPU's TDP is 55 W, which is low for a 16-core part, but it is designed for high-end laptops. Its average benchmark score is 76212, with a 95th percentile rank against all CPUs.

In Roblox, the CPU's role becomes apparent at 1080p. The fact that 1080p Low only reaches 505 FPS, while 1440p Low reaches 337 FPS, suggests that the CPU is not the sole limiter at 1080p; otherwise, the frame rate would be the same regardless of resolution. The scaling from 1080p to 1440p is 33%, which indicates that the GPU is still doing significant work at 1080p. However, the CPU's impact is visible in the frame time consistency. At 1080p Medium, the min FPS is 391, which is 69 FPS below the average of 460. That is a 15% dip, which is larger than the 4K Medium dip of 15% as well (148 min vs 174 avg). The absolute variance is much higher at 1080p, suggesting CPU scheduling or single-threaded bottlenecks.

The CPU's nearest rivals include the Intel Core Ultra 9 285HX, which has a nearly identical average score. In Roblox, the 8945HX's high single-thread score of 6030 in Cinebench R23 is likely important, since Roblox is known to be single-thread dependent. The CPU's boost clock of 5.40 GHz is very high for a mobile part, which should help in lightly threaded scenarios. However, the combo rank of 628 suggests that the CPU-GPU pairing does not achieve the top tier in this game, possibly because the 16-core design is overkill for Roblox's thread count.

The CPU's L3 cache of 64 MB is substantial, and its DDR5 memory bandwidth of 83.2 GB/s is adequate. The data does not show any memory bottleneck, as frame rates do not collapse at any resolution. The CPU's role is to feed the GPU with draw calls and physics updates, and at 1080p, it manages to deliver 505 FPS on Low, which is a strong result. The fact that Ultra at 1080p still hits 330 FPS shows that even with increased settings, the CPU is not the primary constraint at that resolution; it is only when the GPU has less work that the CPU's limits become more visible. The benchmark results indicate that this CPU is more than capable for Roblox, but the overall combo ranking is held back by other factors, likely the game's engine not scaling perfectly with this particular high-end configuration.