I had many problems with the Dual Channel role for Kingston ram in that board I ended up trading it in for some Crucial Ram that starts in auto detect at 8,3,3,3.5 but later I set it to 7,2,2,2.5 it is very stable and the bios stops reporting the memory failed memory test at boot-up like the Kingston stuff was occasionally.
Running two sticks of the Crucial at 512MB in Dual Channel role in slot 2 and 3 as the manual asks for.
Got great bench marks and the ram defaults to a 200MHz that's X 2 for DDR so 400MHz no sweat but I have done that with a 2800+ and a 3200+ in 2 systems using the A7N8X Deluxe.
Your 2600+ might not be stable at those speeds in a dual channel role the Kingston ram was failing Dual Channel at 7,2,2,2.5T set to also aggressive settings in the BIOS.
I would recommend the Corsair Dual channel matched set they come in the same package factory tested to match and they are fully heat dissipated with heat spreaders they also have functional L.E.D lights on the back of each chip that shows functionality.
I have had absolutely no problems running the Crucial 512MB DDR 400 memory at 7,2,2,2.5T it is simply fantastic in this A7N8X Deluxe board.
Now the 2800+ System has Corsair memory at the same settings but that RAM was expensive but I upgraded the 2800+ before I built the 3200+ and since the 3200+ took off like a rocket with the Crucial cheaper ram installed I am hesitant to swap the more expensive Crucial ram into the 3200+ all this is because both systems are running so very well why take the chance mucking with them besides my nerves are shot as far as ESD failures go and I would not want to risk it because the Crucial ram came without heat sinks on them and I had to purchase those and install them onto the RAM chips and that's about as much handling as I wish to do with all 4 pieces of ram for a while.
Since we as humans do not feel a ESD shock discharge until 5000 Volts with no current and all it takes to blow a single pathway inside a computer chip is 5 Volts or to partly damage it causing a chance of latent defects I hate handling my CPU's or RAM and do it as little as possible.
Besides up here right now its been so cold and dry just walking across the room is cranking up 25000 volts you cant turn on a light switch right now without getting hammered by a whopping shock.
I have a complete ESD work Bench and ESD discharge equipment here with Metre lights built into the bench for the wrist strap but still..
Barton 3200+ 400MHz
Liquid 12 Celsius
2x512 Crucial DDR 400 PC3200
Two Maxtor 40Gig 8MB cach 7200rpm
SONY RW 52x/24x/52x
SONY DVD 16x/40x