need help in modding bios KT400A /K7VT4A+

Is your memory not fully recognized? (Intel VX chipset Memory recognition)
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Posts: 1
Joined: Fri Feb 25, 2005 12:45 pm

I just rebuild my kids' machine with
Asrock K7VT4A+
Sempron 2.2 (9*166)
512 M DDR3200 (2.5-3-3-8)
Thermaltake ALCU????
Geforce 4Mx
I was able to reach better than Sempron 2.5 perf with 9*200 by jumpering the CPU FSB and setting DDR 400Mhz and overvolting +10% in the bios

Using Everest, I was happy to see the chipset clock to be 67MHZ, (QDR) which must mean that the AGP divisor is WORKING
So far, so good

The problem
I noticed the memory setting of ASROCK suck badly
the ram is being driven at 2.5-5-4-9 instead of 2.5-3-3-8 indicated by SPD

I am currently playing with WPCREDIT and WPRCSET.
I have not found the KT400A datasheet. I have used the KT266 pcr as a starting point.
I modified offset 64 bits 7 and 6 from 11 to 10 to get RAS from 9 to 8
and bits 2 and 3 from 11 to 01 to get RCD from 5 to 3
Changed offset 69 DRAM queue bit 5 and 4 from 10 to 01 (overall hex value from 2D to 1D)
Changed D5 policy bit 4 and bit 1 (overall hex value from 1C to OE)
memory read (Everest): from 2146 to 2267 : 4.8%
memory write (Everest) from 604 to 711: 17.7%
Latency (Everest) from 136,5 to 134: 2%

Is anyone knowledgeable with the KT400A chipset ???

I would like to know :
1/ how to get RP down to 3
2/ If anyone is skilled in editing the AMIBIOS 1.3 and flashing it
the only tool I have found able to read the bios file si AMIBCP 7.51.03
I got the bios file from ... +.htm#bios
I got the pcr file from
3/ what are the hidden features of the bios

Because I would like to make the change permanent instead of having to load PCRset at every boot.

Posts: 3153
Joined: Thu Mar 21, 2002 8:16 pm
Location: Near Hannover (CEBIT) Germany

Try this site :

They often have unofficial Asrock Bios with more settings available - sometimes they have unofficial performance Bios versions.
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