OBS x264 Veryfast vs Medium Preset Performance

Choosing the right x264 encoder preset in OBS Studio is crucial for balancing stream quality and system performance. This article compares the “Veryfast” and “Medium” x264 presets, analyzing their differences in CPU usage, video quality, and hardware requirements. While “Veryfast” offers excellent performance with minimal CPU impact, “Medium” delivers superior image fidelity at the cost of significantly higher processing demands.

Understanding x264 Presets

In OBS Studio, x264 is a CPU-based software encoder. The presets (ranging from Ultrafast to Placebo) do not change the bitrate; instead, they determine how much time and processing power the CPU spends analyzing and compressing each frame of video.

• Faster presets (like Veryfast) prioritize speed over compression, using less CPU but resulting in lower quality per bit.
• Slower presets (like Medium) prioritize compression efficiency, using significantly more CPU to achieve better image quality at the same bitrate.

CPU Usage and Performance Impact

The most drastic difference between Veryfast and Medium is the demand placed on your processor.

• Veryfast: This is the standard preset in OBS for software encoding. It is highly optimized and puts very little strain on modern multi-core processors. It is the ideal choice for single-PC streaming setups, allowing you to play demanding video games and stream simultaneously without experiencing in-game lag or dropped frames.
• Medium: This preset is computationally expensive. It requires exponentially more CPU cycles to encode the same video compared to Veryfast. If you try to run Medium on a single-PC setup while gaming, you will likely encounter “Encoder Overloaded” warnings in OBS, leading to stuttering video and dropped frames. Utilizing Medium successfully usually requires a dedicated streaming PC or a high-core-count processor (such as an AMD Ryzen 9 or Intel Core i9) with headroom to spare.

Visual Quality and Compression Efficiency

While the Medium preset demands substantially more power, it rewards viewers with better visual output, which is especially noticeable at restricted bitrates (such as the 6,000 to 8,000 Kbps limit on Twitch).

• Veryfast: During fast-paced movements (common in first-person shooters or racing games), you will notice more pixelation, macroblocking, and blurriness. Because the encoder has less time to process the frames, it cannot compress high-motion scenes as cleanly.
• Medium: The encoder performs a much deeper analysis of temporal and spatial data. This results in a sharper, crisper stream with significantly fewer compression artifacts during high-motion scenes. Textures, grass, and fine details remain intact rather than turning into a pixelated blur.

Summary: Which Preset Should You Use?

• Use Veryfast if: You stream and game on the same PC, have a standard consumer processor (6 to 8 cores), or want to prioritize in-game frame rates and overall system stability.
• Use Medium if: You use a dedicated dual-PC streaming setup, have an extremely powerful high-core-count CPU, or stream low-motion content (like tabletop games, art, or talk shows) where the CPU overhead is lower.