ok cryminal, here goes
first of all, let me clarify something. its not the gfx that is causing the lag, period. and the graphics, some little settings in the graphics applet can be lowered with NO (i repeat, NO. did i say no?) differences in gameplay, and the rest can be set to high, at 1024x768. DotA is very little resource hungry game. So to cap it off, no, its not the graphics card, or the CPU. i think the problems you stated can be for some particular PC's, where all the options are lowered and there are graphical anomalies. its not the same with all the pc's there honestly
the problem lies in the hub colliding, which can be solved with a very high quality switch and better cables. The problem is faced due to the massive number of PC's in assault(how many are there in uttara? just asking, nothing against uttara honestly). that should be solved by picking the best PC's for every game played, i.e the ones which arent known to spike(or do u guys play 2 at once? i dont know..)
and yes, dont whine over how good your dota graphical settings are with your pc, i dont want to brag over my pc (but you can trust me its faster than anyones pc here in these forums, even bd most probably, atleast cpu wise

), and yeah every time i go over to assault, i have ZERO problems with graphical settings, but most options to high, and some little settings to low. problems solved, unless im faced with spikes, which, as i stated above, can be somewhat solved
and theres a home match, and a away match! you do get an advantage on your turf, no? im sure the spikes arent as bad as you can feel when ur playing for liverpool, and 80000 arsenal fans are booing you in their home ground whenever you get the ball. theres always a disadvantage playing away.
happy gaming, and best of luck for the tourney! cheers