SLI Using Dual PCIe 16x vs 8x - How Much Bandwidth is Needed? Linus Tech Tips

This video investigates how PCIe bandwidth affects SLI performance using a dual GTX 580 setup, focusing on 16x and 8x configurations. Linus swaps PCIe slots on a Gigabyte G1.Gaming (G1 Honor) motherboard to compare two GTX 580s running in 60x bandwidth versus two cards at 8x bandwidth, keeping the testbench centered on CPU bottlenecks by using an overclocked Core i7-960 on an X58 platform. The test methodology relies on a synthetic benchmark, 3DMark 11, to quantify performance differences as bandwidth changes. In the initial run with full bandwidth, the system achieves a 3DMark score of 3386, and later the two-card setup is tested again with reduced bandwidth, yielding a score of 3389 in one configuration. Linus then contrasts the results to determine the practical impact, noting that the observed improvement when moving from 8x/8x to 16x/16x is a tiny fraction, around 0.01 percent, suggesting minimal performance degradation at reduced PCIe bandwidth for high-end GPUs. The conclusion emphasizes that on Intel platforms, even high-end GPUs like the GTX 580 are not significantly bottlenecked by PCIe bandwidth at 8x, supporting the idea that many users can opt for 8x/8x SLI without major drawbacks while benefiting from lower-cost or more flexible motherboard choices. The video ends with a reminder to subscribe for more hardware testing and reviews, reinforcing Linus Tech Tips as a resource for PC enthusiasts evaluating motherboard and PCIe configurations in real-world scenarios.

Topics · computer_hardware · graphics_cards · pci_express · multi_gpu_sli · performance_benchmark