I think I might have solved the problem <knock on wood>
The bad news is I don't really know how. :/ Here's what I did:
0. Stock values on all hardware frequencies (in the GPU's case stock=superclocked)
1. removed all expansion cards
2. removed one of the RAM sticks, so I had 1GB
3. loaded fail-safe defaults in BIOS
At this point the computer failed to boot. I thought that's just great - it fails to boot with "fail-safe" defaults. Now isn't that ironic? I must admit I was close to smashing the junk against a wall.
4. I accessed BIOS and disabled ALL onboard devices I didn't need: floppy controller, PATA controller, COM and LPT controllers, audio, LAN (I use a cable modem on USB) and some others I can't recall now.
5. Boot to Windows successfully and... voila! 3DMark06 finished the test with a modest 8000 points.
6. I ran the test three times and it passed with ease.
At this point I began resetting the hardware config:
7. I plugged the second stick of RAM to get 2GB - test passed
8. I plugged my Xonar DX audiocard - test passed
9. I plugged in my trusty old TV tuner - test passed
I was beginning to wonder "what if"
10. I overclocked and overvolted the CPU to 3GHz and 1.4V and 3DMark06 gave me hitherto unseen 12000 points!
Not bad for a computer dated 2007.
Now the question is: what was the problem? The only answer that comes to my mind is RAM after all. OCZ claims that their memory should run at 2.1V. When I loaded fail-safe defaults it returned to standard 1.8V and I didn't touch that. After all the tweaks that I did having loaded fail-safe, this is the only value that is different from the previous buggy setup. Interestingly, higher voltage is recommended by the producer (OCZ) and didn't give any errors in Memtest.
Oh well... the computer seems to work fine now, so I don't want to mess with those settings any further.
don't think that there is much in common with video cards made in 2001, and video cards made in 2009... and the error message "infinite loop" is just about as prevalent for ati as it is for nvidia, 36,900 search results vs. 43,600:
Yep, I was too hasty to throw stones. After some further reading I reached a conclusion that "infinite loop" is a generic error that shows up in hundreds of cases and can be caused by multiple config blunders. It probably MIGHT indicate faulty hardware but is often just a software conflict.
yes, i think that you should underclock it, back to the standard 8800gts timings, and then keep going down with the frequencies until it stops failing that test... i have seen at least one account of a defective superclocked gtx 260, that failed only when it was used with the superclocked timings.
Luckily, this was not the case
It runs fine with factory overclock.
EVGA doesn't give a lifetime warranty in Poland
It's only two years and they have already passed. I did register the product within 30 days of purchase so theoretically the card should be covered by the 10 years EU warranty. We shall see, the time for it has not yet come.
I would like to thank everyone who took their time to reply in this thread. Your help is much appreciated!