A normal non-GPU PCIe x4/x8 slot that you'd use for a NIC provides 25 W.
For a 25G NIC, I’d be perfectly unsurprised if it demanded an x16 slot. I’d be more surprised if it didn’t have a power connector like a video card, though.
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For a 25G NIC, I’d be perfectly unsurprised if it demanded an x16 slot. I’d be more surprised if it didn’t have a power connector like a video card, though.