Hi Chris, There are a few areas to look, particularly your firewall config, also, profile your cpu usage so you can get a picture of what processes are consuming the CPU then we can provide further advice from there. Are you maxing out a core with firewall or networking processes? The other place to look is queuing, fq-codel can be your best friend in times like these. Regards, Dirk -----Original Message----- From: Public <public-bounces@talk.mikrotik.com.au> On Behalf Of Chris Lee via Public Sent: Friday, March 1, 2024 1:33 PM To: MikroTik Australia Public List <public@talk.mikrotik.com.au> Cc: Chris Lee <chris@datachaos.com.au> Subject: [MT-AU Public] High CPU and latency spike on RB750Gr3 during downloads Hi all, Am running RB750Gr3 firmware 7.13.5 with the out of box factory configuration for internet router. I have disabled RSTP on the bridge. On NBN FTTP 100/40 plan with NTD connected to eth1 on the RB750Gr3. Rest of my internal LAN is connected to eth2. When I max out a download or run a speed test at 100Mbps I find the CPU on the HEX is getting up to 30-35%, and on upload around 20-25%. At the same time I see in all my pings beyond my first hop ISP gateway that I get a big spike in latency which feels like the Mikrotik is struggling to process the traffic inbound. I thought the RB750Gr3 was good for up to Gigabit speeds, but even then I'm only asking for 100Mbps - is there anything I need to tweak further in the configuration to fix this or should I be looking at a newer router like the L009 series, will that provide smoother throughput ? Thanks, Chris _______________________________________________ Public mailing list Public@talk.mikrotik.com.au http://talk.mikrotik.com.au/mailman/listinfo/public_talk.mikrotik.com.au