WiFi incredibly slow compared to LAN

[MarchingBandWidth]

We have a Cisco 5508 WLC controlling 53x AIR-AP2802I-Q-K9.

current image is 8.5.171

We are experiencing under 10Mbps speed and at best ~20Mbps while when connected on wired, we get ~600Mbps

Most clients are Apple Macbook Pro laptops and on using 5GHz radio

Both LAN and WLAN are on the same topology.

Any guidance on where to begin to troubleshoot this issue? Any output I should be looking at? I am newb to wireless 

thanks

[balaji.bandi]

Is that worked ever better, from day 1 you see this issue, what is the changes done before working vs now ?

is this issue only MAC books , how about Windows PC ?

how is your speed testing mechanism, when do you local transfer using Wifi ? what speed you get ? 

how is your path to reach internet - wired v/s wifi ?

have checked on the path any errors and conection issue ?

troubleshooting tips :

https://community.cisco.com/t5/wireless-mobility-knowledge-base/wifi-troubleshooting-cheat-sheet/ta-p/3108889

check config analyzer :

https://developer.cisco.com/docs/wireless-troubleshooting-tools/#!wireless-config-analyzer

[MarchingBandWidth]

I am seeing a lot of dropped packets on the link between the WLC and our Core switch (WS-C3750X-24S)...

CS#sh interf g1/0/1
GigabitEthernet1/0/1 is up, line protocol is up (connected)
Hardware is Gigabit Ethernet, address is a0ec.f978.dc01 (bia a0ec.f978.dc01)
Description: Port 1 WC1.HND1:CS-WC
MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 33/255, rxload 35/255
Encapsulation ARPA, loopback not set
Keepalive not set
Full-duplex, 1000Mb/s, link type is auto, media type is 10/100/1000BaseTX SFP
input flow-control is off, output flow-control is unsupported
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:16, output 00:00:00, output hang never
Last clearing of "show interface" counters 1d01h
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 696944
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 137318000 bits/sec, 21631 packets/sec
5 minute output rate 133289000 bits/sec, 21081 packets/sec
965016680 packets input, 777227106120 bytes, 0 no buffer
Received 5389863 broadcasts (5303607 multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 5303607 multicast, 0 pause input
0 input packets with dribble condition detected
960957159 packets output, 761389196240 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 unknown protocol drops
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier, 0 pause output
0 output buffer failures, 0 output buffers swapped out

Could this be the issue? I cleared counters and less than a day later, the output drops have already gone up (see output showing output discards after just 1 day)

[balaji.bandi]

you have provided the inputs we asked so hard to judge the what is the issue ?

regarding interface output, change the SFP and chagne the patch and check. (some time you see the drops, if the interface overloaded? )