AAccording to the 2024 VideoToolBench performance test, Synthesia Pro is currently the fastest online AI video generator. The average time consumption for generating a 1-minute 1080p video is only 58 seconds (RTX 4090 graphics card). It far exceeds similar tools such as Runway ML (1 minute and 42 seconds) and InVideo (2 minutes and 15 seconds). Its distributed rendering technology can maintain a real-time speed of 3.8 times when processing 10-minute long videos (with a total time consumption of 2 minutes and 37 seconds), optimize the video memory usage to 4.2GB (competitors require 6.5GB), and support the simultaneous processing of 8 video tasks (competitors average 3). For example, the advertising agency @AdGenius used Synthesia Pro to batch generate 100 15-second advertisements. The total time consumption was compressed from 9.5 hours of traditional tools to 2.1 hours, with an efficiency improvement of 352%.
In terms of hardware efficiency, Descript also performs well in CPU mode: With the Intel i9-13900K processor, it takes 1 minute and 12 seconds to render a 1-minute 720p video (0.9 times real-time speed in GPU mode), and power consumption is only 98W (versus the average of competing products at 160W). NVIDIA’s 2025 tests demonstrated that its CUDA core utilization was 92% (industry average was 78%), and usage of video memory in rendering 4K videos on the RTX 4080 card was 37% less compared to Pictory (5.8GB vs 9.2GB). However, dynamic light and shadow rendering accuracy is relatively low (ΔE*94=3.7, and 1.2 in commercial applications such as DaVinci Resolve), resulting in a 18% increase in high-end project rework rates.
Of the free alternatives, the free version of Lumen5 stands out for generation speed: it creates a 1-minute 480p video in 2 minutes and 48 seconds (3 minutes and 12 seconds for the free version of Dreamlux), but the resolution limit leaves the SSIM (Structural Similarity Index) at only 0.76 (0.91 for paid alternatives). User scenarios show that education institution @EduFast used Lumen5 to produce course videos of 30 minutes in length. The dropout rate for the students increased by 23% with the low resolution. After they shifted to Synthesia, they saw a boost in completion rates by 41%.
On the cost and legal risk side, the fastest tools are very expensive: Synthesia Pro’s price is 588 per month, while the chance of infringement risk is 0.1 times per thousand generations (average for free tools is 1.2 times). A 2024 GettyImages lawsuit revealed that a customer who used unauthorized materials unintentionally to make videos using free software paid one 2,400 yuan compensation, resulting in a total loss of 28,000 yuan within the year. In terms of hardware depreciation, with heavy usage (average of 3 hours per day), the lifespan of the RTX4090 decreases from 5 years to 2.5 years, with an average annual cost increase of 620. Cloud-based solutions (e.g., Runway ML Enterprise Edition) can reduce this to $0.18 per minute.
Technical bottleneck comparison: InVideo’s H.265 encoding efficiency has an SSIM of 0.89 (industry best) at a bit rate of 15Mbps but with only a processing speed of 1.2 times real-time (Synthesia Pro has 3.5 times). For 4K HDR material, the time of generation of Descript (4 minutes and 22 seconds per minute) is 217% more than that of DaVinci Resolve, while the subscription cost of the latter is 53% greater (295/month vs192/month). The final choice requires a balance between speed, expense and quality – Synthesia Pro is perfect for the moneybags (with a 290% ROI increase), while small teams can try out the free version of Lumen5 (with an unstated cost of $0.38 per minute) as a stopgap.