Asuswrt-Merlin RT-AC88u Router download speed decreasing

[audioquest]

When I reboot the router, my download speed is 52 Mbps , after a few days the speed start decreasing, about a week later speed decreasing to about 35 Mbps
Once I reboot the router download speed is back to 52 Mbps. Is there a configuration setting that might help resolve my problem

Thanks

 

[JGrana]

If it helps any, I once had a slow slowdown of download speed on an AC88u. When looking at spdMerlin plots you could clearly see this gradual slow down.
I tried many things. I believe it was @RMerlin that mentioned cables.
Sure enough, the cable between my AC88u and Arris cable modem was the culprit. Changed to a new one and never saw the speeds drop again.
Easy enough test at least!

 

[audioquest]

Thanks,
I swapped out my Linksys wrt1900acsv2 router with the AC88u
Never had this problem with the Linksys, but I will give it a try and swap out the cable and report back

 

[audioquest]

If it helps any, I once had a slow slowdown of download speed on an AC88u. When looking at spdMerlin plots you could clearly see this gradual slow down.
I tried many things. I believe it was @RMerlin that mentioned cables.
Sure enough, the cable between my AC88u and Arris cable modem was the culprit. Changed to a new one and never saw the speeds drop again.
Easy enough test at least!

Do you use a Lan or ethernet cable connecting your routers

 

[JGrana]

Do you use a Lan or ethernet cable connecting your routers

I tend to think of them as the same. It was an Ethernet cable between the two.
What was interesting was that the decay was somewhat logarithmic over time.
If you don’t have spdMerlin installed, install it and let it run a week or so. The speed graphs should be pretty “level”.