Verizon FiOS → Where do i change my mtu setting on actiontec?

I have an actiontec router MI424WR-GEN2(REV E.) I need to change my mtu to play xbox but i dont know in which section im suppossed to change it in.

Why do you need to change it? The default is automatic (1500 if you're on DHCP). Any other value can adversely affect your performance.

The XBOX site states MTU must be a minimum of 1364 (which it is).
»support.xbox.com/support ··· mtu.aspx

However, if you insist on changing it, there are separate MTU settings for you WAN connection and your LAN.

WAN Setting:
•My Network
•Network Connections
•Broadband Connection (ethernet or coax as appropriate)
•MTU = MANUAL, enter desired MTU size
•APPLY

LAN Setting:
•My Network
•Network Connections
•Network (H/O)
•MTU = MANUAL, enter desired MTU size
•APPLY

You should not need to change it. i've tried Xbox Live over the last few years on at least six of my Xbox 360s through the actiontec with zero issues.

actually i have no probelm logging into xbox live. The problem is mainly when i play a ranked online fifa 10 match. My connection becomes extremely slow and lagged. It feels like im playing in super slow motion. I tried making my actiontec a bridge while using my d link for routing a while back. I changed the mtu setting on the d link to 1400 with great success. It was like a night and day difference. My gameplay was lightning quick but i dont want to use the dlink anymore, instead i would just like to use the actiontec router. I want to see if changing the mtu on the actiontec will work the same way it did when i was using the d-link. I noticed there are multiple locations to change MTU settings but i dont know which ones i am suppossed to change. Do i change all of them?

Change the two I posted above.

If you change only one, the router will have to reblock packets from one MTU size to the other (applies to packets larger than the smaller of the two MTU sizes).

ok but under the home/office, there are 3 underlying connections...
there is...

ethernet
coax
wireless access point

if i am understanding correctly, i am only suppossed to change the mtu setting in the Network(Home/Office) section and not to all of them?

Yes, just in Network (Home/Office).
[edit to add]not in the underlying devices.

Also, change the same setting in your Broadband Connection.

Size of packet would be whatever your research has determined to be the optimal setting. Then after you've changed the settings, you'll need to evaluate all your network services to understand the impact of the new MTU value.

Run a speed test, browse web pages, stream video, do whatever you'd normally do, keeping in mind the before and after for comparison.