Long round trip times on local net

[raymond.meyer%rambler.ru@localhost]

I have two machines running NetBSD-5 beta, i386 and sparc64. Both
machines are on a local network. When I ping i386 machine from sparc64 I
notice the following output:

64 bytes from 192.168.0.40: icmp_seq=49 ttl=255 time=0.261 ms
64 bytes from 192.168.0.40: icmp_seq=50 ttl=255 time=0.254 ms
64 bytes from 192.168.0.40: icmp_seq=51 ttl=255 time=1000.276 ms
64 bytes from 192.168.0.40: icmp_seq=52 ttl=255 time=0.416 ms
64 bytes from 192.168.0.40: icmp_seq=53 ttl=255 time=0.258 ms
64 bytes from 192.168.0.40: icmp_seq=54 ttl=255 time=1000.250 ms
64 bytes from 192.168.0.40: icmp_seq=55 ttl=255 time=0.391 ms
64 bytes from 192.168.0.40: icmp_seq=56 ttl=255 time=0.256 ms
64 bytes from 192.168.0.40: icmp_seq=57 ttl=255 time=0.264 ms
64 bytes from 192.168.0.40: icmp_seq=58 ttl=255 time=0.275 ms
64 bytes from 192.168.0.40: icmp_seq=59 ttl=255 time=0.257 ms
64 bytes from 192.168.0.40: icmp_seq=60 ttl=255 time=1000.249 ms
64 bytes from 192.168.0.40: icmp_seq=61 ttl=255 time=0.386 ms
64 bytes from 192.168.0.40: icmp_seq=62 ttl=255 time=0.264 ms
64 bytes from 192.168.0.40: icmp_seq=63 ttl=255 time=1000.248 ms
64 bytes from 192.168.0.40: icmp_seq=64 ttl=255 time=0.388 ms

Quite a few packets show round trip time of just over a second. If I
ping sparc64 machine from i386, the round trip time for all packets is
about 0.200 ms, i.e. there are absolutely no over 1 second delays.

Does anyhone know why so many packets have such long delays? The i386
has a PCI network card that uses rtk driver, sparc64 uses hme driver.
I've tried different CAT cables on both machines, which didn't make any
difference. Can this be a hardware problem or a driver bug?