Hello, i have an x570 motherboard - 3950x and i bought here the noctua chromax i cannot install it i do not have my backplate, will this fit?

It should fit any AM4 socket motherboard. I was surprised at how well it slotted in place.

Questions & Answers: AM4 CPU Cooling Fan Bracket Cooler Heatsink Holder Retention Bracket for AM4 (for AM4's Heat Sink Cooling Fan Mounting Clip-ON Type only)

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AM4 CPU Cooling Fan Bracket Cooler Heatsink Holder Retention Bracket for AM4 (for AM4's Heat Sink Cooling Fan Mounting Clip-ON Type only)

AM4 Retention Bracket & AM4 Back Plate (for AM4's Heat Sink Cooling Fan Mounting)