I never heard of being able to A.I.unlock the av8 30%?..were did you get this info from maybe it will explain there?
If you really want to play about trying to up your mhz to 2.6*and have the 1008 bios* then instead of choosing 10% A.I. in your bios change it to manual this will open your fsb and multiplier setting's EG..11 multiplier x 200 fsb=2200=amd 3500+ or 11 multiplier x 235 fsb=2585 also go into your memory option's and change memclock to 2.1 ratio this will keep your memory insync with your proc fsb.
This is a REALLY basic method how to oc the amd 3500 on a av8 so i would seek advice else where first and i would forget about oc'ing anything using the stock heatsink and fan.
Also if your mobo is not.a rev 2 which i dont believe the deluxe version is your very limited on oc'ing your proc as the deluxe version hasnt got a agp/pci lock meening uping the mhz on your proc=unintentionally upping the mhz of pretty much everything else=
From what i've read it's widly regarded that the 3500+ will go stable upto 2.4mhz=3800+speed's so i reckon your a bit out your depth looking for 2.6mhz.
In all honestly i've never even tried to oc my setup*yet*which is similer to your's for the simple reason there is no need to plus when i get my paw's on an x800xt there'll defo be no reason for some time to come..
Reading over your post's it seem's your on a mission for a NEED FOR SPEED but your running amd3500+,av8,and 6800gt grfx but only 512 of ram which is probably why you feel your not getting the result's in game's.
I would suggest if you dont know much on oc'ing or even if you did for that matter to forget about it and save your pennie's for another 512 stick of ram or 1 gig of branded duel channel ddr to take advantage of the 3500 duel memory controller then you may appreciate your setup alot more......and with alot more reason too.

amd 3500+,
asus av8,
36 gig wd raptor,
80 gig diamondmax p9,
radeon 9800 pro 128 mb,
enermax noisetaker 470 watt.