This summary of the video was created by an AI. It might contain some inaccuracies.
00:00:00 – 00:13:10
The video comprehensively explores the impact of different PCIe generations, particularly PCIe Gen 3 and Gen 4, on the performance of high-end GPUs like the Nvidia RTX 4090. It performs extensive testing, including synthetic and gaming benchmarks, to measure theoretical and real-world throughput differences between these generations. The findings indicate minimal performance variances—typically within 1-4%—except for some notable outliers such as a significant 15% performance gain in "Total Warhammer 3" at 1080p with Gen 4 over Gen 3. The speaker also touches upon aspects like driver optimizations and the diminishing relevance of PCIe bandwidth in typical gaming scenarios, particularly for older systems. Throughout the video, they highlight that while higher PCIe generations offer slight performance improvements, the difference is often negligible for most users.
00:00:00
In this part of the video, the presenter conducts PCIe bandwidth testing to examine the generational impact on the RTX 4090 when using PCIe Gen 3 versus PCIe Gen 4. Although Gen 5 PCIe was tested, the RTX 4090 doesn’t support it, so it had no effect. The focus is primarily on Gen 3 vs. Gen 4, with additional insights into the usefulness of comparing 8 lanes versus 16 lanes. It is mentioned that PCIe Gen 4×8 is similar in bandwidth to PCIe Gen 3×16. The testing involves multiple passes to ensure accuracy and reliable data. Background details about PCIe generational support, CPU-level requirements, motherboard configurations, and lane utilization are provided to illustrate what impacts performance differences. Additionally, a sponsor segment highlights the features of the Montex Sky One Lite PC case.
00:03:00
In this part of the video, the speaker discusses the relevance of PCIe generations and their impact on device performance. They clarify that features like Crossfire and SLI are no longer supported and focus instead on the PCIe Gen 4 capability of the Nvidia RTX 4090. They explain that the necessity of higher-generation PCIe interfaces depends largely on whether devices can fully utilize the offered bandwidth. Historical examples, such as SATA hard drives, are used to illustrate this point. The speaker also notes that PCIe generation becomes crucial when lane count is reduced, which can significantly affect performance. An overview is given on the maximum theoretical bandwidth for PCIe Gen 3, 4, and 5, and mentions future generations like Gen 6 and Gen 7. The segment concludes by introducing the first task: a PCIe bandwidth test via 3DMark to measure maximum theoretical throughput.
00:06:00
In this part of the video, the speaker discusses the testing and performance results of different PCIe generations using a specific synthetic workload. The test shows no real-world application directly matching the synthetic workload, though it’s acknowledged that such applications might exist. The Gen 5 motherboard configuration yields similar results to Gen 4 due to the lack of Gen 5 support in the test card. The theoretical throughput is compared across PCIe generations: Gen 3 drops significantly to 13 GB/s, Gen 2 further to 6.7 GB/s, aligning closely with expected overhead and specifications.
The crucial point highlighted is the BIOS toggle’s functionality, confirming the accuracy of their testing method. When moving to gaming results, Total Warhammer at 1440p provided the most notable difference, with PCIe Gen 4 outperforming Gen 3 by approximately 3.6% and a more extreme 15% difference at 1080p, leading to retest confirmations due to the large performance variance observed. Nvidia’s performance lab has been consulted for further validation.
00:09:00
In this segment, the video discusses potential issues and results from testing NVIDIA driver optimization and PCIe bandwidth behaviors. It mentions an outlier found that may be tied to a combination of PCIe bandwidth and driver behavior. Testing hundreds of games would be needed to find more such results. Performance comparisons for Shadow of the Tomb Raider, Final Fantasy 14, Rainbow Six Siege, and Strange Brigade showed slight differences in FPS averages between PCIe Gen 3 and Gen 4, generally within a 1-3% range. An unusual outlier was noted in Total Warhammer 3 at 1080p, demonstrating a 15% range difference, prompting further investigation.
00:12:00
In this part of the video, the speaker discusses the impact of PCIe bandwidth on gaming performance. They note that while comprehensive testing across hundreds of games is required to find consistent patterns, generally, PCIe bandwidth is not a significant concern for most users. Specifically, if you’re using a high-end video card, the difference in performance between PCIe Gen 3 and Gen 4 interfaces is minimal, typically within a 1-4% range. The speaker mentions that for those using older systems, the issue is mostly negligible. They also encourage viewers to visit their store and subscribe for more focused follow-up testing on new CPUs and GPUs.