Squid3 over OpenVPN issues

I have a group of proxy servers, which I distribute lots of different requests through. This works fine which I use the local network ip address, but when I use the VPN ip address I get random request timeout issues.

Now I know the request url is working fine, and the VPN seems to be stable (no packet loss when pinging) but I can't figure out what is going wrong.

This only seems to happen when there are multiple requests and is like the VPN is limiting requests. Were talking around 3mb/sec and the connection can handle much more than that.

How can I debug this further? I've added my OpenVPN config below.

port 1194
proto udp
dev tun

ca ca.crt
cert mycert.crt
key mykey.key

dh dh2048.pem

server 10.8.0.0 255.255.255.0
ifconfig-pool-persist ipp.txt

push "dhcp-option DNS 208.67.222.222"
push "dhcp-option DNS 208.67.220.220"

client-to-client
keepalive 10 120
comp-lzo

user nobody
group nogroup

persist-key
persist-tun

status openvpn-status.log

verb 3