This is strange because my dad recently bought a X1650 (but by Sapphire) to install on ASUS A8V motherboard. Except him it would not even reboot after POST, it would stay stuck in POST.
So what he did was to get PCI-E motherboard with Sapphire HD 2600PRO, now works perfectly.
By googling, I was able ,to find quite a lot of people that are having problems with this card, more specifically the AGP 8x version.
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