A home network upgrade to 10Gb/s hit a snag when MikroTik SFP+ modules began overheating in summer weather. One module in the study switch reached 93C and started 'flapping'—repeatedly shutting down at around 95C for self-protection. The Marvell-based modules were notorious for heat issues, as discussed on Hacker News and Serve The Home forums.

Research pointed to Broadcom BCM84891 PHY chip modules as more power-efficient alternatives. The author swapped the problematic MikroTik unit for a 10Gtek ASF-10G-T80-INT, which promises ultra-low power consumption at 1.6W for 10Gbps over copper. Installation required careful latch removal, assisted by a YouTube tutorial.

The replacement module worked immediately but presented an odd quirk—it impersonated an Intel fiber-optic transceiver instead of revealing its true identity. Temperature monitoring via SNMP disappeared, likely due to different OID reporting. However, CPU temperatures on the switch dropped about 5C, and the network stabilized without further flapping during subsequent hot weeks.

This real-world case highlights significant thermal differences between SFP+ module generations. While older Marvell-based modules struggle with cooling, newer Broadcom designs offer better efficiency for sustained 10Gb/s operation in residential environments.