Skid said:
That's a pretty big difference.
The most significant is memory. Some of the cards sold as 9700 Pro are
actually underclocked because the memory won't run that fast. In many cases,
more than one type of memory was used on the same model from the same
company, so you could actually order two PowerColor cards, for example, that
had different memory specs. The bios on the cards set different speeds and
timings based on the memory modules used. There were small differences in
performance at stock speeds and major differences in overclocking
capabilities.
The other difference is the PCB. Sapphire, for example, offered two
different 9700 Pro models, one red and one black, that had different
characteristics and performance.
For details, there are some good head-to-head comparisons of Radeon brands
and models at
www.xbitlabs.com
Thanks for that, Skid. But, Guy, surely the real question is, why
_wouldn't_ different OEMs make their cards differently? They all have
different sourcing for materials, different manufacturing processes,
different design teams, different standards, different markets - the list is
endless. What on earth makes you think that every OEM's card is going to be
exactly the same?
For myself, I have a Sapphire 9600 Pro VIVO card. ATi don't even make a
VIVO card in any range above the 9000s now, I think, but various OEMs
probably produce, between them, a VIVO version of every ATi range. In
addition, All-In-Wonder cards are made to different specifications for
different regions; ATi's own are, AFAIK, all NTSC models now. I would have
thought from the claim in your sig that you would be aware of that.
And those are glaringly obvious differences. As Skid has pointed out, there
are other clear visual and component differences. Another obvious one is
cooling solutions.
But, apart from that, different OEMs obviously have different design
philosophies. My VIVO card is a clear example of that, and many OEMs have
taken the decision to produce card versions that ATi don't make. Some OEM
cards won't run ATi's MMC software. And it's also clear that, concerning
the OP's question, some designs are different enough to benefit from changes
in ATi's drivers; I've found that to be so with an ASUS card, for instance:
it ran much better with ASUS' own versions of the Catalyst drivers than with
ATi's drivers of the same version number.
patrickp