BIOS settings are not as rich on the KD7A as the other 2 motherboards so I did not took any pictures.
To summarize, the parts I used are:
CPU: Athlon XP 2800
RAM: 2 * 1 GB sticks different models but with the same memory timings set in the BIOS. FSB: DRAM = 1:1.
GPU: Leadtek Geforce 7800gs 256mb
PSU: Enermax 465w with 35A on the 5V rail.
Cooler: some copper based model that kept the temperatures in check despite being no name
DVD: some unknown model
HDD: Maxtor 120 GB on AT7; WD 74 GB on AT7 – MAX 2; WD 120 GB on KD7A.
Monitor: Eizo 21.3 inch 1600*1200 LCD.
Windows: XP SP3 with no updates.
Compatibility testing and setting up took around 6 months for all 3 systems; actually testing the performance took only 2 months! The video card is running without a single problem on all 3 from the outset. Ram: it was quite difficult to find 1 GB sticks compatibles with AT7 – MAX and MAX 2: only the particular modules seen in the pictures work without errors when using aggressive settings, on KD7A the first modules I put in worked with no problems.

First to test is the Code creatures benchmark. The order in which results are posted will always be: 1. AT7; 2. AT7 - MAX 2; 3. KD7A. Resolution used are: 1024*768 - the most common resolution of the CRT era and the 90's; 1280*1024 - used today when we got an abundance of 17-19 inch LCD but also back in the day when testing powerful CPU/GPU combinations and supported by all games from the 2000's; 1600*1200 - for the very high end CRT and LCD, very demanding, like 4k today. I also tested with sound on and off when possible but, to be clear, the codecs used on all 3 boards are not very different and all processing is done by the CPU! There is no hardware accelerated sound. Using a Creative sound card would have made all 3 systems equal and could not pinpoint if any one of them is actually better equipped in the sound department.
AT7 at the 1024*768 resolution:

AT7 at the 1280*1024 and 1600*1200 resolutions:

AT7 - MAX 2 at the 1024*768 resolution:

AT7 - MAX 2 at the 1280*1024 and 1600*1200 resolutions:

KD7A at the 1024*768 resolution:

KD7A at the 1280*1024 and 1600*1200 resolutions:

First test and what can we see? The difference between all 3 chipsets is quite small; reviews back in the day stated than even KT400A which has an improved memory controller has 5% better performance than KT400 despite being just an updated version of the KT400. Not today when we have the best possible CPU, GPU and updated drivers.
Please note that testing with memory out of sync - that is DRAM set at 400mhz on the AT7-MAX 2 for example - will always result in a penalty!

Next we switch from DirectX 8 to DirectX 9 with Aquamark 3.
AT7 on the 1024*768 resolution:

AT7 at the 1280*1024 resolution:

And finally AT7 at the 1600*1200 resolution:

We upgrade now to the AT7-MAX 2:
1024*768

1280*1024:

And the most demanding resolution: 1600*1200

We now upgrade our motherboard one last time to KD7A and let's see if KT400A does provide the jump in performance we were expecting!
1024*768

1280*1024

Finally we reach the 1600*1200 resolution!

Aquamark 3 test shows us that it is worth testing with sound and paints a different picture! All 3 boards are using the Realtek AC97 codec so in theory they should be equal, but they are not! AT7 - MAX and AT7 - max 2 scores are pretty close - within the margin of error - but KD7A jumps ahead by a large margin when using sound! 10.14% at 1024*768 is similar to what nforce2 advantage has over KT880 using onboard sound! The difference remains big at 1280*1024: 9.26%. Even at 1600*1200 KD7A has an advantage of 8.2%! I did retested 4 times and the results displayed by KD7A stayed the same!
The first time when one the boards jumps ahead and secures a clear victory! Let's see if the trend continues!

We now go back in time to a benchmark built around DirectX 7: 3dmark 2000!
Again, first is the AT7 using VIA KT333 chipset at 1024*768, 1280*1024 and 1600*1200 resolutions:

Next is the AT7-MAX 2 with VIA kT400 chipset at 1024/1280/1600 resolutions: