CRS326, 6.42.3: Simple queues causing high load?

RouterOS Beginner Basics
1

Hi,
in a home office setup my CRS326 has 2 bridges (for the ‘real LAN’ and a guest LAN) configured to forward Internet traffic from the ISP’s DSL modem/router to the local users. I want to control and limit the bandwidth of specific users / IPs. Doing so by using Simple Queues works quite well.

My question is if this should cause the high CPU load I’m experiencing:
40 Mbps (about 3.500 p/s) = 90% CPU load
50 Mbps (about 4.000 p/s) = 100% CPU load
70 Mbps (about 6.000 p/s) = 100% CPU load
100 Mbps (about 8.000 p/s) = 100% CPU load
(test traffic came from speedtest.net)

The CPU load looks about like this:
Sniffing 35%
Networking 27%
Management 14%

Although it seems that the BW limitation works even with a 100% CPU load, I wonder if this is correct or if there is a misconfiguration.
I did the same with a RB750Gr3 (880 MHz dual core): There is also high CPU load, but it can master the traffic from from my 100 Mbps DSL with Simple Queues without reaching 100% CPU load.

Is the CRS326 with its 600 MHz single core under-dimensioned? Or is there a way to optimize my setup? Thanks!

2

“The CPU load looks about like this:
Sniffing 35%
Networking 27%
Management 14%”

Disabling Sniffing will already give you back 35% of CPU

3

Thanks a lot, CZFan!
I assumed that the sniffing is a task of the queuing, “sniffing” some packet attributes before making a decision. Now I understand that its a different job which I activated while exploring the OS and forgot to deactivate it. Now I get about 35% CPU load with 100 Mbps flowing through the device. Great! Enough spare power for me!