Originally posted by WildStyle
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DFI NF4 BIOS
Newer BIOS' for these boards will come in 3 versions. You will, for example, notice a 623-1, a 623-3 and a 623-3. (BTW, boards will always ship with the latest official general/unoptimised BIOS i.e. if you bought an nF4 Ultra-D now it'd arrive with the 623-1 BIOS).
-1 = General BIOS for all RAM. Not optimised for any particular type.
-2 = Optimised for BH/UTT BH/UTT CH.
-3 = Optimised for TCCD/Micron.
BTW, the 623 in the example used above refers to the BIOS being released on the 23rd day of the 6th month (of 2005).
The difference between the three BIOS versions is the ROMSIP table used. A ROMSIP table is the memory controllers internal timings and along with the correct alphas can make a big difference to how your RAM plays. Some configs prefer one ROMSIP type, some another, hence the comments below.
As always, the above is not an exact science, it is merely a rule of thumb. I have seen people running for example TCC5 on a "-2" BIOS with great success yet I have seen people trying to run Micron -5B D in a "-2" or "-3" BIOS and the result was a no POST and a while spent sorting it out. The general BIOS will be fine for most types of RAM, it is really only if you are pushing for stability at high clocks that a BIOS designed for your specific mem type may become useful. With regards to slots, Orange is recommended as they generally work better than yellow, but as always, you should really test for yourself to find out which arrangements work best for you. However, if you're lazy, just follow the recommendations.
If for whatever reason you flash to a BIOS that doesn't like your RAM, and you can't POST or the BIOS hangs, you need to power down, clear the CMOS, put a stick of RAM in the top yellow slot and then power up again. The system should now at least POST, meaning you can then flash to a more appropriate BIOS either from within DOS or via WinFlash in Windows.
