How to Reduce RX packets drop Count

Dear Guys,

I have one Fortinet 3810A.

CPU Utilization of port5 CPU 3 getting high.

Below is the drop count.

Can any one help to resolved issue  

CPU states: 3% user 26% system 0% nice 71% idle CPU0 states: 3% user 2% system 0% nice 95% idle CPU1 states: 9% user 3% system 0% nice 88% idle CPU2 states: 1% user 0% system 0% nice 99% idle CPU3 states: 0% user 99% system 0% nice 1% idle Memory states: 23% used Average network usage: 167177 kbps in 1 minute, 154112 kbps in 10 minutes, 156543 kbps in 30 minutes Average sessions: 26693 sessions in 1 minute, 30982 sessions in 10 minutes, 41630 sessions in 30 minutes Average session setup rate: 347 sessions per second in last 1 minute, 339 sessions per second in last 10 minutes, 370 sessions per second in last 30 minutes Virus caught: 0 total in 1 minute IPS attacks blocked: 0 total in 1 minute Uptime: 28 days, 11 hours, 23 minutes

fnsysctl ifconfig port5 port5 Link encap:Ethernet HWaddr 00:09:0F:09:00:0D UP BROADCAST RUNNING PROMISC ALLMULTI MULTICAST MTU:1500 Metric:1 RX packets:76058910314 errors:281860847 dropped:2222804762 overruns:2354023381 frame:0 TX packets:18066553615 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:100 RX bytes:40569316191014 (37783.1 GB) TX bytes:5795007645199 (5397.0 GB) Interrupt:28 Base address:0xc000 Memory:edd00000-edd20000