Hello people, im Fire on the game, and i just learned a way to remove some lag from the game.
I readed all the tutorial here: http://forums.spiralknights.com/node/48
and i pickuped some part from there.
This worked for me:

You will need to try and set Spiral Knights to its minimum display settings:

1. Close Spiral Knights (if it's running).
2. Click on the 'Start' menu and then click on 'Run'.
3. Type in "regedit" and hit 'OK': this will bring up the Registry Editor. Warning: Please do not change anything else in the registry since it could cause severe problems.
4. Browse through the registry tree and expand to 'HKEY_CURRENT_USER\Software\JavaSoft\Prefs\projectx'
5. Double-click each of the below registry keys (if present) and type in the corresponding value:

display_mode = 512, 300, 0, 0

Here are other values that may reduce more:

15/16 of default window: 960, 562, 0, 0
7/8 of default window: 896, 525, 0, 0
13/16 of default window: 832, 487, 0, 0
3/4 of default window: 768, 450, 0, 0
11/16 of default window: 704, 412, 0, 0
5/8 of default window: 640, 375, 0, 0
9/16 of default window: 576, 337, 0, 0
1/2 of default window: 512, 300, 0, 0

And the rest... Are insignificant because you wont see anything.

6. Close the Registry Editor and start Spiral Knights.

And thats that!
You will notice some reduction in 1/4 of your window from SK but will definately notcie high reduction from lag.

If you want to get back to the default, just select at the options the resolution you want.

And thats all people, it worked for me, if it wont work for you im sorry.

Previews:
5/8 of default window: http://i51.tinypic.com/1zt10x.png
1/2 of default window: http://i52.tinypic.com/2mww7z4.jpg