different vlan speed on 1941 router

[ciscoreg2]

Hi;

I configure router divise to 2 vlans on 1941, and I setup a EHWIC-D-8ESG card, make 4 and 4 ports to each vlan.

I found computer in same vlan, file transfer speed is OK, about 100mb/s.

But computer in different vlan, file transfer speed is maximum 30mb/s.

So what kind of reason  cause this problem? how can I do to speed up? below is my conf could you have a check?

interface Vlan126

 ip address 192.168.186.1 255.255.255.0

 ip nat inside

 ip virtual-reassembly in

 ip tcp adjust-mss 1452

interface Vlan192

 ip address 192.168.188.1 255.255.255.0

 ip nat inside

 ip virtual-reassembly in

 ip tcp adjust-mss 1452

interface GigabitEthernet0/1/1

 switchport access vlan 126

 no ip address

interface GigabitEthernet0/1/7

 switchport access vlan 192

 no ip address

[Palani Mohan]

No. Intra-VLAN should achieve lineRate OR near lineRate.

[Joseph W. Doherty]

It might, if you're doing inter-VLAN routing.

If traffic remains with the same VLAN, and on the same module, then you should not be impacted by CPU performance.  However, even if on the same VLAN, if you need to jump between interface modules, you might bump into other hardware performance limitations.

Understand the 1941 was designed as a low bandwidth WAN router, that can provide additional local ports that ideally only want to interact with other WAN reachable hosts.

If you want high performance between VLAN hosts, you might need a separate device or insure you use an Ethernet module designed for that purpose on the 1941.