ASA-5506-X Very slow internet speeds

[MDIusMDIus]

I've had the ASA-5506-X in place for a couple years now. 1 Failed earlier this year and replaced it using a backup configuration. Set this up with out issues. We use Comcast internet and our down is 75mps and up is 15mps. Never had any issues with speed till last week. Down is now 40 and up is 1. My PC is plugged in to a gigabit switch that is directly plugged in to the ASA from the Arris Sufrboard SB6121. If I plug in to the modem direct I get 90 down and 17 up. If I plug directly in to the ASA I get the 40 down and 1 up.

I've tried to reset it, unplug for 30 seconds and plug in about 3 times and re-installed the backup config too.

Nothing is working to improve the speeds.

Any ideas?

[balaji.bandi]

First place i will ask, is there any rules or changes to the FW compare to last good known config.

Other side check the port-negotiation and any errors. if possible change Ethernet cables both the sides to eliminate any hardware issue.

Since its not major network FW, if this home based as per my understand, Clear all the config, make it simple config and test it..if that is working then we need to look the rule base.

Do you have IPS modules or policies enabled ? Check the MTU ?

look the troubleshoot guide for refernce :

https://www.cisco.com/c/en/us/support/docs/security/asa-5500-x-series-next-generation-firewalls/113393-asa-troubleshoot-throughput-00.html