I've been trying to build... basically "the best" socketA system to run WinXP and some games on.

Yes, i am aware that this is not the best idea - the CPUs are not fast enough for many games and hardware is becoming problematic/expensive to get. But... i still want to because i really like the platform. I've had a lot of fun with it back in the day, still have my old system (K7VTA3 v8, AXDA2200DKV3C, 2x512MB DDR333, FX5900XT) which works fine and basically want to compare it with "the best".

So i've acquired a bunch of hardware for this. Mostly from scrappers in unknown condition with intention to repair if broken, because this way prices are reasonable. This includes:

- AXDA3200DKV4E, AXDA3000DKV4D, AXDA2500DKV4D, AXDA2000DUT3C, AX1700DMT3C CPUs. This all work and 2500+ one is nice enough to "just work" if set to 400 FSB, so 3200+. And this one i am mostly using for my testing as they are common/cheap while finding another actual 3200+ one may be a pain if i break it (always a chance when swapping coolers).

- A few nForce2 Ultra 400 based boards: EP-8RDA3I, EP-8RDA, GA-7N400S-L. Epox ones had bad caps, like all of the larger ones. CPU VRM on both sides and those scattered around the board. I recapped them, to be honest - without paying too much attention to specific cap series and with salvaged (from dead ~modern hardware) caps. This worked, though i do not have proper power supply for EP-8RDA which has 5v VRM and while i did test it - this is quite painful for modern PSUs. Gigabyte one is seemingly in great condition, no visibly bad caps, works. Did have exploded diode near ATX connector which i replaced, so that's not a good sign, but given everything seems to work should not be the cause of my issues. And that's the one i want to use for my build because of 2 USB headers and SATA ports (which are quite nice, work with modern SSDs, have decent performance and good compatibility).

- Whole box of various RAM, though all this seems to be relatively simple RAM, nothing high-end, so perhaps i have to try to get something better. But my intention is not overclocking so i thought that regular DDR400 should be good enough, especially with dual channel and everything. Though now that i've ran into issues i probably should try to get something better.

- A few videocards (this are the expensive part...) - GF7600GT 256MB GDDR3, HD2600XT 512MB GDDR3, GF6600 128MB DDR1. And some random passive FX5200 for testing because it is dirt cheap and convenient. I am aware that this are not really period correct, but my interest is in platform itself and i wanted a card which would be powerful enough to certainly not become a bottleneck. This have been tested, they work, and so far i'd probably choose 7600GT because of better cooler and less driver issues (I hate AMD drivers. Both back then and now. Guess can call me nvidia fan, not because of hardware, but because i prefer when it actually works without crashing all the time). But i will reconsider if there is a good reason to, after all 2600XT is more modern and does seem faster.

- Modern PSU. be quiet system power 9. This was intended for the build as it is quiet and should be more than sufficient. Though when i ran into issues i did test with Corsair HX850 for a good measure - does not change a thing.

So... now that i've described the hardware.... the issue:

I've tested everything with EP-8RDA3I (i got it first) and both CPUs - overclocked AXDA2500DKV4D and actual AXDA3200DKV4E. Cold not find a pair of 1GB sticks of RAM which work well, but that's to be expected. 1GB total should be sufficient for now and i have much bigger variety of 512MB sticks. So i've ran memtest86 stupid amount of times and this resulted in most sticks working just fine in dual channel configuration. I've picked and thoroughly tested 3 sets, even with slight overclocking by setting timings to 2.5-3-3-7 instead of 3-4-4-8 the board defaults to. Installed XP, tested GPUs, etc. All worked as it should. Though i did encounter a fair bit of memory issues during my testing, so guess people were not kidding about nforce2 being picky.

Now... i wanted to switch to GA-7N400S-L and it all went downhill from here. It does not work with 2 DDR400 sticks, at all. I mean it posts, but memtest finds issues right away and any attempt to boot OS, even linux live CD, fails. Single stick works, in any slot. DDR333 works, though this does affect performance significantly for some reason (again - seen a lot of people saying it is better to run 1:1 FSB:RAM with nforce2). BIOS is being annoying too - there are no actual voltages displayed, just "ok", and no way to adjust voltage. So, i resorted to multimeter and discovered a few interesting things - gigabyte board overvolts all the things, slightly. RAM is ~2.75, CPU is ~1.7. Epox board undervolts things - CPU is ~1.6, RAM is ~2.6. Can this be a consequence of using a bunch of random caps? It works fine though with a bit lower voltages and does have controls in BIOS, so i can bump them up if i want to and this has no affect on already working configuration (as expected). I've put AXDA3000DKV4D into gigabyte board and that works just fine, RAM and everything. But i want "the best", right?

So i am stuck. All the info (manual etc) and common sense seem to indicate it should just work. But it does not. Especially surprising with higher voltages. I could just go with epox board (and probably acquire a couple of better 1GB sticks later anyway), but SATA and extra USB are really useful. Or i could get more boards. But... i am just curious at this point. Am i doing something wrong? Is the board faulty in some way (perhaps should try to recap)? Is it simply a bad board and has been sold like this? Would not surprise me from gigabyte... Would really appreciate any advice on trying to troubleshoot this...

I am sorry for a wall of text, many of this is probably irrelevant but i just wanted to give all the info i can since i have no idea what is going wrong and may not understand the significance of some info...