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The guy is a hack.

Ask him for a screen shot.

I guarantee the card is running as an 8800GT.

When 9800GT came out, Nvidia authorized their partners to re-flash 8800GT with the 9800GT ROM. The "real" 98GT G92 is a die-shrink with built-in powersaving feature to allow built-in GPU on PC boards, but otherwise identical.

These shrunk G92s could in theory run a TOUCH faster if the ROM is set to higher speeds. This guy has probably just flashed with Mac 8800GT ROM, so 100% identical performance to Mac 8800GT, but nothing better.

Ask him for that screenshot or an OpenGl page showing the card running as 9800GT or informal benchmark comparing to a 8800GT in same Mac.
 
the 9800GT and the 8800GT are the same tho, same specs and everything except the chip, the 9800GT has a lower NM, so its really hard to tell
 
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