I made a budget gaming computer -- AMD X2 Athlon 3600+ and 7600GT
(both overclocked). I ran Oblivion at playable framerates at almost
maximum settings. My colleague says that his new computer with 8800GTS
struggles to run Oblivion at maximum settings, and he wonders why I
can ran it on my computer. I run Bioshock at maximum settings, and the
game has no speed problems (that is, it runs at least at 20 fps). And
yet the reviews show that the high-end cards (like 1950Pro and 7900GT)
struggle to run the game at full settings.

What is happening ? Maybe my GPU card is better what it is claimed to
be (it is a grey import from China). The other consideration is that
both mainboard and the GPU are from the same manufacturer, MSI, and
the mainboard has an nVidia cheapset (like the videocard). Maybe the
GPU and the mainboard have an improved compatibility, which results in
an improved performance ?

This looks less likely so, because I ran the tests Mark3D03 and
Mark3D05. It came out that the unoverclocked computer had a
performance at the bottom of the surveyed computer systems of the
equal specifications. After overclocking, my computer performed the
test very closely to the median of the similar systems they tested.

That gives ?