Slow PIX 501 performance

Question

PIX 501 connected to a residential cable modem. Speedtests are giving me 3mbit down. When I plug a machine into the cable modem I am getting 10-12mbit.
Posting pertinent info:
interface ethernet0 auto
interface ethernet1 100full
nameif ethernet0 outside security0
nameif ethernet1 inside security100
pager lines 24
mtu outside 1500
mtu inside 1500
ip address outside dhcp setroute
ip address inside INSIDE_IP 255.0.0.0
ip audit info action alarm
ip audit attack action alarm
pdm logging informational 100
pdm history enable
arp timeout 14400
global (outside) 1 interface
nat (inside) 1 SUBNET1 255.255.255.240 0 0
nat (inside) 1 SUBNET2 255.255.255.240 0 0
nat (inside) 1 0.0.0.0 0.0.0.0 0 0
timeout xlate 0:05:00
timeout conn 1:00:00 half-closed 0:10:00 udp 0:02:00 rpc 0:10:00 h225 1:00:00
timeout h323 0:05:00 mgcp 0:05:00 sip 0:30:00 sip_media 0:02:00
timeout sip-disconnect 0:02:00 sip-invite 0:03:00
timeout uauth 0:05:00 absolute
aaa-server TACACS+ protocol tacacs+
aaa-server TACACS+ max-failed-attempts 3
aaa-server TACACS+ deadtime 10
aaa-server RADIUS protocol radius
aaa-server RADIUS max-failed-attempts 3
aaa-server RADIUS deadtime 10
aaa-server LOCAL protocol local
aaa authentication ssh console LOCAL
http server enable
no snmp-server location
no snmp-server contact
snmp-server community public
no snmp-server enable traps
floodguard enable
telnet timeout 30
ssh 0.0.0.0 0.0.0.0 outside
ssh 10.93.44.0 255.255.255.0 inside
ssh timeout 60
console timeout 0
terminal width 80

Answer 1

Ensure that the speed and duplex negotioated for the outside are correct, issue a "show interface e0" and see if you have any input/output errors.
HTH>