OST are junk. you can trust them with your stuff if you want but not me. I will LMAO at you when those OST caps dead short circuit and destroy something. Like I said they do not have to show any signs of failure before they go out. They can read ok in a cap esr check and still fail without warning …

The original battery was dead (about 1V or so), I've replaced it with new one and it showed ~3 volts. So it seems the battery is ok and motherboard doesn't perform any strange things besides that. I will look for capacitors brand. EDIT: yes, there are some OST branded caps, another bunch is named …

What is the battery voltage showing on a multimeter? If that motherboard is made by ECS look to see if it has OST brand of caps installed. Those are known to go bad without showing any visible signs.

Not enough information given. Beware. That PSU that comes from the InWin case could be a 5 volt heavy unit only capable of powering a PIII board. Athlon64 boards are normally powered from the +12V line. Use exteme caution before using such an PSU.

Untested in translated ebay language means the seller has already tested it and found that it does not work but will not admit that to you.

Not from that seller, 115 negative feedback in just one year, no thank you.

Since these card are becoming somewhat rare and not so cheap I suggest installing a fan to blow more air on the card and thus not risking unrepairable damage to it.

Look for a BIOS update. That is what fixed that same issue on my M748LMRT ver. 1.3D I used the last known BIOS revision dated 2001. Hope that helps.