Performance problem old hardware

Hi, my hg659 fibre router is cutting out, however I have openwrt on the old vdsl modem hg556 and set it up to work wifth fibre (thanks to this site)! However I only get 33mb/s throughput from pc to the router (and internet) with iperf (100mb connection) and full 100mb between the two computers on the same hub , i think it should be more powerful since vdsl can go past 50mb.

Is it the way I have setup the vlan ? on the pic above port 3 is the wan
If i delete vlan1 and put all pcs on vlan10 will it work better ?
Last time I deleted vlan1 I had to factory reset, however I didnt set the PC ports to "untagged so I guess they were on "off" .

Im in New Zealand its required to set vlan10 ,

I checked the cpu use with the webpage live updating and iperf running together and it is maxing out the cpu...
if i set each PC port to untagged and all on vlan 10 and get rid of vlan1 will it be better?
Perhaps alter some firewall settings, seems like alot of rules there, its just default settings on OpenWrt Chaos Calmer 15.05.

I'll probably just grab a second hand hg659 anyway, but hey im learning something new.

Sounds like you identified your problem.

Thanks, here is the utilization at ssh terminal

Im using ethernet it shows hostapd as highest which seems to be wifi related..

With wifi disabled its less than 80% but still throughput is the same.