Solution between 2-way splitter and fan hub. I've usually seen fan hubs where you can add 6 to 8 fans. Since the fan header on the motherboard is usually set at 1 amp, I would be afraid to use more than 5 fans depending on the fan type. While a two-way splitter doesn't take full advantage of your port. I made a build for my brother using a budget motherboard with limited fan headers and greatly upgraded the fan options for his case.
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