In theory this should not be a problem, it is just a sign that speed step and cxe is turned off. So it is more like a warning than the cause of the problem. I reduced the multiplier to 6 from 8, but it is unplayeable. I'll try with low quality later.
I got back my old video card, I'll test it tomorrow, but I am afraid it won't be enough for b4. Maybe at low quality or low resolution. Anyways I will be able to test whether the problem is with the new video card + driver, or with the mobo+cpu+ram+bios settings+psu, etc... I'll check the system with the other pair of ram too.