when NVIDIA bought out the defunct
company 3d effects they acquired their
patents and intellectual property
including the trademark sli name that
had been used to describe 3d effects is
system for using multiple graphics cards
working together to achieve better
gaming performance but by the time they
reintroduced sli to consumers its
underlying technology had undergone some
very significant changes let's see just
what made the very first generation
nvidia sli tick after this message from
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all right so in the late 90s 3dfx made a
handful of now-famous blunders first
they decided to manufacture their cards
themselves as opposed to just selling
chips and providing reference designs to
add in board partners but because their
new Factory couldn't compete on either
quality or cost with Taiwanese and
Chinese based AI bees Oh Liam
relationships that they had hoped would
come never materialized to their focus
on raw horse power rather than modern
features allowed NVIDIA to steal the
market share crown from their flagship
voodoo3
then put the nail in their coffin with
the GeForce 256 which arrived earlier to
the market and was vastly
technologically superior to the delayed
napalm core that they used in the Voodoo
4 and voodoo 5 3dfx filed for bankruptcy
in 2002 so then it only took two years
for Nvidia to decide that selling two
graphics cards rather than one per
customer is pretty cool and rollout SLI
again except that this time it stood for
scalable link interface rather than
scanline interleave this is because
instead of having each card render
alternating lines of a single frame
Nvidia opted to use two new approaches
to splitting the rendering load between
the two cards in alternate frame
rendering or AFR each card takes turns
rendering a full frame this was the
preferred method and typically resulted
in the best performance scaling and in
split frame rendering or SFR the 3d
scene would need to be broken down
horizontally depending on geometry load
with one card assigned to render the
bottom part of the frame while the other
handled the top now via both of these
methods whether it was outputting half
of every frame or alternating full
frames the secondary card would send its
output to the upper or Master Card via
the brand-new 400 megahertz one gigabyte
per second SLI can
then that top card would output the
final image to the screen now it was
this high bandwidth connection that gave
invidious solution both its name and its
high performance all right well
sometimes high performance you see
without a software sli profile the
second card would remain either
completely unused or even end up hurting
performance and because the system had
no way of knowing on its own which sli
rendering settings would work best for a
given game it was up to the driver team
to hand validate both brand-new games
and some significant older titles so
this process was more work than you
might think and it wouldn't be until
many driver updates later during the
summer after lunch that the green team
would ship their 100th SLI profile now
let's talk about the hardware
during the first unveiling Nvidia was
actually using a Zeeland platform based
on the 7525 chipset for its newfangled
high-speed PCI Express expansion slots
but despite these demos being originally
run on an Intel chipset Nvidia ended up
requiring users to purchase a
motherboard that was equipped with an
SLI ready variant of Nvidia zone and
force for chipset now the successful
user modification of non sli certified
boards raised quite a few questions
about whether this was an artificial
limitation designed to help Nvidia
maintain a foothold in the chipset
market but I digress
the next thing you needed was a powerful
CPU to keep both cards well fed with
data so we're using an overclocked
Opteron that will give us similar
performance to the fastest CPU at the
time the single core 2.6 gigahertz FX 55
third a good 24 pin ATX power supply was
strongly recommended now the 6800 GTS
that we have in here their TDP is only
67 watts and our whole system
pulls only about 260 watts from the wall
under load but there's more to a quality
power supply than just wattage one
having a suitable 12 volt rail
distribution was absolutely necessary to
keep it from just turning off when you
fire it up a game and two native PCI
Express power connectors were a definite
bonus at the time so you didn't have to
use adapter dongles onto the cards
themselves SLI technology required
pretty much identical cards like this
pair of matched XFX 6800 GTS and
initially even the BIOS revisions on the
cards needed to be the same though that
did ease up over time to the point where
even slightly mismatched cards would
equalize according to the clock speeds
of the slower card finally a well
ventilated case was a must most of the
cases from this era used 80 millimeter
cooling fans
so especially given the poor design of
the reverse blowing single slot cooler
on our card it was common to Seaside
intakes modified into cases after the
fact like this one and even with our
extra airflow our cards hit a toasty 85
degrees under load now let's look at
performance Nvidia cited 1.8 7 X scaling
and synthetic benchmarks but our own
testing gave us one point six for one
point eight two and one point seven six
though it should be noted that when it
comes to real games we actually managed
an amazing one point nine eight percent
scaling in half-life 2 and we saw up to
one point eight six in farcry so in
essence this tech when it worked would
enable you to step up to the next image
quality and/or resolution level and
what's cool is that the higher the load
the better it scaled furthermore unless
it ran out of VRAM which does not add up
between the cards it sits cloned the
system took games from the next-gen like
fear which was so demanding it initially
shipped with a 1024 by 768
maximum resolution from cinematically
playable to actually playable and before
you ask yes yes indeed it can add a
mixture of medium to low settings this
machine produced over 40 FPS at 1024 by
768 in a game that came out three years
after this card launched neat right now
let's talk downsides and oh there were
plenty the expense of a fast CPU sli
ready board and power supply aside
alternate frame rendering introduced a
temporal artifact known as micro
stuttering where the frame rates were
high but some users reported choppy or
jittery in-game animations and this tech
lived and died by the existence of an
SLI profile with some games whether by
design or due to just not getting around
to it never ending up working with SLI
meaning that that second card that you
bought was a terrible value if your
favorite game didn't end up scaling
furthermore there were some general
quality of life issues including but not
limited to the fact that two cards is
louder than one changing SLI modes
required a system reboot at the start
your second monitor would go black once
a game was fullscreen and I had this
bizarre issue with azureus BitTorrent
client remember that where it and
Firefox if they were running at the same
time
SLI would disable itself but still show
enabled in the control panel unless kind
of goes on so bottom line
despite its first generation flaws SLI
when it worked was so powerful that it
exceeded in videos next generation 7900
GTX is performance making it really
freaking cool when it works
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first purchase we're gonna have that
linked below so thanks for watching guys
massive shout out to Benoit Pierre for
sending us a working sli motherboard for
our tests like this video sucked you
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