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Fluctuating PCI e speed during render test.


New Member
Apr 8, 2021
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The bus speed will fluctuate between x16_2 and x16_3 during the GPU Z render test. It seems like the speed is locked at 16x3 when I put games in Windowed mode and monitor the bus speed. I have a 3080, a 10900k and an MSI Unity z490. I set the bus speed to Gen 3 in the bios, my benchmarks all seem fine in game and synthetic. Is this just a matter of the render test not really loading the GPU enough to have it consistently run and x16_3? Seems like it only happens when I use the small windowed version of the test. Full screen test meant for SLI is using the full speed of the slot.

Last edited:
Apr 28, 2011
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Botevgrad, Bulgaria, Europe
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May 14, 2004
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Is this just a matter of the render test not really loading the GPU enough to have it consistently run and x16_3
Yeah this can happen on the most powerful GPUs nowadays