Interesting! Never noticed this with anything before 11.3 personally but to be fair I upgraded to them around 2 1/2 weeks ago then to 11.4 yesterday. Really annoying issue though as I get absolutely slaughtered a the start of every game due to it :S
Glad I'm not the only one though!
One thing that is different ... I can't remember if this lag started before or after is that I now run everything from 2 x 1TB in RAID0, before I was running Steam and the game from a separate drive in AHCI mode. The RAID set-up benchmarks better as you would expect, nevertheless, I have changed things so just thought I'd better mention this.
Left perfmon and CCC running on 2nd monitor while in-game. This start of round lag, same whether shader warmer is on or off (this was a fix for lag way back iyrc) and there is no more CPU or GPU usage during this time. One thing I did spot, if I join a started game, I get no lag! It's only after being in from the very start. I asked others on Ventrilo, hehe, they said ffs Jeff, just turn the damn lagometer off, you'll enjoy it much more ... they have a point