Why do I get "Output Buffer Failures"?

[RadiusCat]

Please see the sh int fa0/24 below. I am getting output buffer failures for some reason. Could this be a bad nic, cable, etc???

FastEthernet0/24 is up, line protocol is up
Hardware is Fast Ethernet, address is xxxx.xxxx.xxxx(xxx xxxx.xxxx.xxxx)
MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive not set
Auto-duplex (Full), Auto Speed (100), 100BaseTX/FX
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output 00:00:01, output hang never
Last clearing of "show interface" counters never
Queueing strategy: fifo
Output queue 0/40, 0 drops; input queue 0/75, 0 drops
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 5000 bits/sec, 5 packets/sec
196479 packets input, 82918914 bytes
Received 185 broadcasts, 0 runts, 0 giants, 0 throttles
3 input errors, 3 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 0 multicast
0 input packets with dribble condition detected
1584081 packets output, 421849260 bytes, 40 underruns
0 output errors, 0 collisions, 1 interface resets
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
40 output buffer failures, 0 output buffers swapped out

 

[dopehead]

Hmm, 40 buffer underruns as well ? Seems like maybe something is sending to small packets ?
Also 40 packets out of 1,5mill isn't really a problem.

Jan