In my opinion its your guys connections. I've had plenty of 4v4s (never got a 5v5 going befor .. but yet haven't tried since beta patch).
It isn't software i don't think because you can eliminate it and still have the problem. Dead Ghost says even on 2 different drives / OS installs he still lags.
So honestly guys its your connection not demigod ... you just have a very weak weak broadband connection. PC gaming takes a big demand on your connection and your PC specs.
I run this game full evreything without a single bit of lag and could play any game with any amount of players and have no issue. From what i've seen is that you guys have a very very very veryyyyyyyyyyyyyyyyy crappy upload but that isn't what is always hurting you ... you guys barley seem to pull 5 Mbps on the DOWN when the speedtest server you are testing is only ~50miles away (a.k.a Protocept00).
Computer Specifications
My specs:
Processor: Intel Core2 Quad Q9400 @ 2.66GHz (4 CPUs), ~2.7GHz
Memory (RAM): CORSAIR 4GB (4094MB) DDR2 (PC2 8500) Dual Channel
Hard Drive: Intel X25-M 80GB Sold-State Drive (SSD)
Video Card: NVIDIA GeForce 8800 GTS 512MB
Sound Card: Realtek High Definition Audio (Good soundcard on my mobo)
And my vista boot time is around ~20sec to desktop.
Connection
Next is connections .... i don't know how much this game takes connection wise but with my connection i am never even concerned. But after looking at some of you guys and seeing what your speed test showed.
My connection is Comcast and this is my speedtest (NOTE: I was downloading a torrent on another PC on my network at the time of this speed test. I was roughly DLing around ~150KB/sec and uploading around 200KB/sec during this test).

So see i personally think its your connection and maybe some of your PCs (Keyword: MAYBE since i don't know most of your guys PC specs) if they aren't strong enough. If the processor or the PC is getting bottlenecked it could cause you to lag but from what i've seen your guys connections are just extremely weak and i don't think they can handle more than a 2v2 because if you think about it ...
2v2 = 3 ppl for your PC to talk to and your PC has to relay everything your doing to them so their client can show your charcter doing what your doing.
3v3 = 5 ppl for your PC to talk to ... and upload your movements.
5v5 =9 ppl for your PC to talk to ... and upload your movements.
So thats just my 2 cents
. Hope it helps!
(Post Edited to fix picture).