The H100 single PCIe max is 350. Dual PCIe with presumably more than one connector as well, 400. However, thats total power to the GPU. Minus the 75 watts that the board supplies, you're looking at 275 and 325 max respectively. Just on either side of half of what the connector is purportedly rated for. The reference 4090 is 450, or 375 through the connector, before overclocking. What's more, the consumer GPUs have significantly nastier power spikes than the commercial GPUs.