PCIe 16x vs 8x vs 4x - Does It Matter??

PCIe Gen 4 vs Gen 3 Slots, Speeds does it matter which pcie slot i use for gpu I'm aware that the bottom two slots are 16 x and the top two are 4x The Sonnet card needs a 16x for the fastest speeds, it's not a 4x card does it matter which pcie slot i use Does Size Matter? Testing a 4-SLOT GPU! Huge thank you to Micro PCIe NVMe SSD

does it matter what pcie slot i use Now, I read somewhere that if you use the top slot, you're giving up 8 PCI lanes shared with the top PCI-E slot So my 4080 would be running