Seanicy, did you mean NB core voltage, or the CPU-NB voltage? The core voltage doesn't need to be adjusted unless you're crossfiring, or trying extreme memory clocks. At least that's what I have found. I do however set the NB core to 1.15v with the NB @ 2800, but only for 2800+.
For the RAM, select the option in bios above the divider (1:4, 1:3.33, 1:2, etc...), and hit enter, this will bring up the page to adjust the timings. On the top option, change it to both, and for the two banks (you'll notice all the adjustable settings will be duplicated down the page, one full set first, then a second full set) you can set your RAM timings. Change both sets of settings as outlined below.
The first four set to 7, 8, 7, 20, skip one and then 27, leave everything else alone. Set your DRAM volts to 1.67v. You should be good to go, I can set it without stepping up to those timings, so you should be able to also, I would think.
Looks good, Moorhen2, get those 4890's overclocked! You will probably have to up the NB-PCIe volts to about 1.2-1.25, and the NB volts as well to about the same. I know I have to do that for my two 4890's, but it allows me to game them @ 1010/1140. With three of those I don't know if you'll need to adjust the HT volts, maybe, maybe not.
Edited by mduclow - 2/7/10 at 12:42pm