Understanding Your GPU Benchmark Results

Frames Per Second (FPS) is the most familiar GPU performance metric, measuring how many complete frames your GPU renders each second. While seemingly straightforward, FPS interpretation requires understanding its limitations and what different values mean for real-world performance.

FPS Ranges and Perception

Why Average FPS Can Be Misleading

Average FPS is a simple metric but hides critical information about frame time consistency. Consider two scenarios:

• Scenario A: Consistently renders 60 FPS with frame times of 16.67ms
• Scenario B: Alternates between 90 FPS (11ms) and 40 FPS (25ms), averaging 60 FPS

Both scenarios have the same average FPS, but Scenario B will feel stuttery and inconsistent. This is why frame time analysis is crucial for understanding true performance quality.

Our Benchmark's FPS Measurement

We calculate FPS using a 60-frame rolling average, providing smoothed real-time feedback during the test. This approach filters out momentary spikes while remaining responsive to sustained performance changes, making it ideal for detecting thermal throttling over 10-30 minute stress tests.

Frame time (measured in milliseconds) is the inverse of FPS: how long it takes to render a single frame. While FPS gives overall throughput, frame times reveal consistency and worst-case performance.

Understanding Percentile Metrics

P95 and P99 are percentile metrics that answer the question: "What's the frame time that 95% (or 99%) of frames are faster than?" These metrics focus on the worst-performing frames, which disproportionately impact perceived smoothness.

Why P95/P99 Matter More Than Average

Human perception is highly sensitive to frame time spikes. A single 50ms frame (20 FPS) in the middle of otherwise smooth 16ms frames (60 FPS) is immediately noticeable as a "hitch" or stutter. P95/P99 metrics quantify these worst-case scenarios that determine perceived smoothness.

Interpreting P95/P99 Frame Times

For competitive gaming or professional visualization, aim for P99 frame times under 20ms (50 FPS). For general use, P99 under 30ms (33 FPS) is acceptable if average FPS is significantly higher.

Stutter Frequency Density (SFD) measures what percentage of frames exhibit significant frame time increases compared to recent history. It quantifies how often your GPU produces "micro-stutters" that disrupt smooth motion.

How SFD is Calculated

A frame is considered a "stutter" if its frame time exceeds the recent average by a threshold (typically 150-200%). For example, if recent frames averaged 16ms and the current frame takes 26ms, that's a significant spike flagged as stutter.

Interpreting SFD Scores

What Causes High SFD?

Common culprits for elevated SFD scores:

• Thermal throttling: GPU reducing clock speeds due to heat buildup (most common in sustained tests)
• Power limit throttling: Hitting power delivery constraints, especially in laptops
• Driver overhead: Background processes or driver issues causing periodic frame drops
• Memory bandwidth saturation: VRAM bandwidth insufficient for workload
• Background applications: Other programs stealing GPU resources intermittently

The Sustained Load Score (SLS) measures GPU performance stability over time by comparing final performance to initial baseline. It's the single best metric for detecting thermal throttling and cooling efficiency.

SLS Calculation

Example SLS Calculation

Interpreting SLS Scores

Why SLS Matters for Real-World Use

Peak benchmark scores often measure performance in short bursts before thermal limits kick in. SLS reveals sustained performance during long gaming sessions, video rendering, or scientific simulations where thermal equilibrium matters more than cold-start speed.

A GPU with 10% lower peak performance but 95% SLS will outperform a faster GPU with 80% SLS in any workload lasting more than a few minutes. This is especially critical for laptops where cooling constraints dominate long-term performance.

Thermal throttling occurs when a GPU reduces its clock speeds to prevent overheating. Understanding throttling patterns helps diagnose cooling issues and optimize system performance.

Thermal Throttling Stages

Detecting Throttling from Benchmark Data

Even without temperature monitoring, our benchmark reveals throttling through performance patterns:

• Gradual FPS decline: Smooth downward trend over 10-15 minutes indicates progressive thermal throttling as GPU heats up
• SLS below 90%: Sustained Load Score under 90% confirms thermal management actively limiting performance
• Increasing P99 frame times: Growing worst-case frame times suggest clock speed fluctuations from thermal cycling
• Rising SFD over time: Stutter frequency increasing during test indicates instability from thermal stress

Improving Thermal Performance

Understanding your GPU's performance in context requires comparing against similar hardware and identifying whether your results align with expected capabilities.

Desktop vs Laptop GPUs

Laptop GPUs with identical model numbers to desktop counterparts typically perform 20-40% slower due to power and thermal constraints. A laptop RTX 4070 operates at 80-115W, while the desktop version runs at 200W+. Adjust expectations accordingly when comparing results.

Architecture Differences

Our volume shader benchmark heavily utilizes floating-point arithmetic (FP32). GPUs optimized for different workloads (tensor cores for AI, RT cores for ray tracing) may perform differently than synthetic benchmarks like 3DMark predict. This provides valuable insight into shader compute performance specifically.

When to Be Concerned

Your results warrant investigation if:

• SLS is more than 10% below expected for your GPU model
• P99 frame times exceed P95 by more than 50% (indicates severe instability)
• SFD exceeds 5% with average FPS above 30 (stuttering despite adequate performance)
• Performance drops significantly below similar configurations in online leaderboards