what gets FPS gpus what gets more FPS
more gpus obviously everybody thinks so
and manufacturers have been working on this technology since the late 90s so
then what the heck happened to it I'm gonna let you know a little secret
come here hide
future now that might seem like a bold
prediction given that NVIDIA just completely removes the multi-GPU links
from their latest generation even on the premium workstation cards but there is a
clear course set for better performance through multi-GPU Graphics Solutions and
the most bizarre part is that it's Apple who ultimately did it to properly see
where we're going sometimes we have to visit the past which is why we got our
hands on this legendary piece of Kit the
quantum 3D Mercury brick is an 8 GPU
design from 25 years ago that has a lot
more in common with your future gaming rig than you probably realize like you
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quantum 3D obsidian 100sb-440v that Ross tregamba
thoughtfully brought along when we shot our Voodoo 5 6000 video the name might
not sound like much but it's a great example of something that the original
3dfx Voodoo one was capable of even if
it rarely did it dual GPU operation in
this case on a single board now these ones were intended for desktop PCS but
the primary purpose of cards like this was to drive arcade machines more on
that later because first I want to talk about the brick this extremely rare
piece of computing history uses a four card setup with each card equipped with
two Voodoo 2 gpus that is eight gpus
running all together on the same workload now I know what you're thinking
that looks like it would have a tough time fitting in a PC that also needs
dedicated cards for sound networking and yes 2D Graphics to run the desktop
because the voodoo 2 was 3D only and
you'd be right about that but again more on that later for now
it's time to see this thing in action I was going to be the one to install the
brick in this simulator chassis from 1999 but understandably the owner didn't
trust me to do it without dropping it so um I didn't but we've got some b-roll of
how it goes in it's wild I mean all four cards need to go into their own PCI
slots then it's got to be wired up to a VGA out and in then it's got to be wired
up to a VGA pass-through at the back of the chassis then these two cables are
wired up to the back for a feature called swap lock that allows more than
one of these than twenty thousand dollar
machines to be utilized at once the rest
of these specs are high end even if relatively mundane we've got dual
Pentium 3500 megahertz processors what appears to be an Intel first party
extended motherboard a mere 425 watt
power supply from the legendary PC power and cooling we've got 256 Megs of RAM a
gigantic sound card that's as big as some gpus today and then a ton of
cooling is especially for the time dual 92 millimeter fans and then a couple
more 80 mils that blow directly down onto the heatsinks over the gpus with
this what looks very handmade shroud let's fire it up
oh
this is part of the simulator experience it needs to sound like it's taking off
wait there's no event for those 80 millimeter fans
they're just yeah it's got enough spacing in there for just okay all right
Windows NT let's go we have a few options for things we can run we could
play games on it which obviously is the first thing I would have done if I
worked at a military installation in one of these showtimes how fast does it run
halfway but we actually also have some simulator
software cool it's so weird seeing a Sierra
splash screen when you fire up half-life
you mean valve right right about okay all the geometry what the what that
stop stop buddy check out the pixelation
whoa the first thing I noticed was that compared to the voodoo 5 6000 the frame
rate is obviously lower what I didn't think to look at
is house move it is what the
this was possible in 1999
I think that's functionally 16 times anti-aliasing this looks
modern cleaner than modern
it looks like a much higher resolution than it is that is wild
like I'm specifically going out of my way to put these straight lines at just
you know ever so slight an angle so that I can see the stairs
it's just not there it really makes the crappy old texture stand out doesn't it
oh yeah like if this had the horsepower to run modern games with modern
resolution textures it would look so
good
blah blah
blah blah got him it's Hardware level anti-aliasing okay that's pretty wild I
think I do kind of need to see it without the hardware anti-aliasing then
okay so how do you uh is that something you can change while the game is running
yes oh no way yeah so no wait wait what
so this is a Medusa cable uh-huh so it's got a 26 spin guy here two bgas so what
we're gonna do is we're gonna bypass this by just plugging into one of the
boards individually so in this case each board is a dual GPU GPU and the other
three boards are just contributing to more anti-aliasing correct yeah so the
bridge is basically combining the image it's basically four instances of voodoo
to SLI okay basically what it is so I'll get the same FPS correct but it'll look
like crap exactly
we're both going pretty much the same place slightly different stages I can confirm
anti-aliasing no longer working now it still looks smoother than it
would on an LCD just because CRTs have they're not really pixels they're more
like dots so they're they're not squared at the edges
but you can really see the difference here oh look especially on objects that
are farther away where the level of detail is lower like those picture
frames yeah that's a big yikes
and the shimmering as I'm moving back and forth that is a big difference not
the kind of difference the average home user would pay for but a difference
nonetheless let's try some simulation stuff it's a non-interactive right I
guess I wouldn't have whatever control cockpit they would use for something
like this
and that is smooth
60fps in 1999
that's the thing we got to remember hold on I'm not I'm not done I'm not done
checking out how smooth the terrain
looks like yeah we're seeing that
whether that's like a frame pacing issue or whether that's just a vsync issue
isn't it pretty incredible how well the AAA Works in this thing
anti-aliasing is unreal
like look at these particle effects like yeah they're not amazing or
whatever but they exist
there's just no other way to put it this machine is mind-blowing but what's most
mind-blowing about it at least to me is that the maker of the brick Quantum 3D
still exists as a producer of simulation
hardware and software if you remember the Evans and Sutherland Sim Fusion card
that we looked at a couple of years ago these guys probably would have been in
competition with that at some point going back to the days of the brick though they sometimes sold enhanced
versions of 3dfx's single GPU cards to enthusiasts with extras like additional
video memory and texture units but their main business was to act as 3dfx's
arcade and simulation division until they were spun off as their own company
in 1997. with that history it makes a lot of sense that they had the know-how
to create Exotic Solutions like these out of voodoo gpus the first known use
of a Quantum 3D card was Ice Home Run Derby in 1996 and a lot of high-profile
games like San Francisco Rush would go on to use them too these were not cheap
solutions ending up insist is costing anywhere from over a thousand to
thousands to in excess of ten thousand dollars but while it would have been
Unthinkable for a home user to spend more than a few hundred dollars on a
gaming device at the time at the high end Quantum 3DS devices were used for
military simulation and even down at the low end they could be expected to
deliver tens of thousands of dollars of revenue for their owners quarter by
quarter over the lifetime of the machine and it's that lifetime that was one of
their big advantages because before Quantum 3D it was quite common for
arcade games to use bespoke Hardware or
at best a platform like the Neo Geo by
comparison Quantum 3DS platform was more or less a PC in all but form factor
which made changing over to a new game even one that requires a hardware
upgrade much simpler and more cost effective than it had been in the past
often game data was even stored on a bog
standard IDE hard drive and because the Glide API that the gpus ran on was
readily available and had a similar syntax to opengl games were much easier
to prototype and develop then as now the hardware is only part of the battle and
the real work is in making it easier for developers to get the most out of it and
get the most out of it they did the additional power on tap from Quantum 3D
cards could be used in one of two ways either as a traditional SLI setup where
the additional GPU or gpus could be used
to push resolutions or frame rates higher than they would be able to
otherwise or as was common in the simulator space to have multiple cards
generate the same image but with rotated
anti-aliasing patterns this was a way for them to Output ridiculously smooth
Graphics in the absence of resolution that was high enough to prevent aliasing
that is how the Mercury brick would have been used and this was actually very
important because in a simulator hard pixel edges can be very distracting
unlike our new circuit desk pad on LTT Store stealthy AF now of course with the
demise of 3dfx came the demise of SLI as the world knew it then but that didn't
mean that companies like Quantum 3D and Evans in Sutherland were left without
Hardware to sell multi-GPU development was seen as essential in the Sim Space
and continued in Earnest even while there wasn't yet an official way to make
it work for major players be they NVIDIA or ATI in fact Alienware even had a
project in the works to run multiple gpus before New Age SLI and Crossfire
came along when those Technologies finally hit the scene though multi-GPU
came back to the masses in a big way with some very interesting
implementations early Crossfire for example required a master GPU that
stitched together the output from multiple gpus rendering different parts
of the scene with an external dongle this method is called split frame
rendering and is similar in concept to how old school SLI used to work it
wasn't ideal though even aside from the hardware complexity this setup limited
the maximum resolution there was also software Crossfire at the time which
allowed dongle free operation directly over the PCI Express bus but PCIe wasn't
as fast then as it is now and it was only really suitable for low end gpus
newage SLI and Crossfire X meanwhile
used Bridges between the Cards themselves which is actually quite
similar to 3dfx's SLI the difference though was that rather than stitching
together scan lines or quadrants of the screen the cards could communicate with
each other over the bridge and divide up their work by each rendering alternating
frames leading to you guessed it a
return to multi-GPU cards like the GTX
590 and Radeon 6990 even three-way and
4-way configurations were possible using multiple Bridges these setups were
gargantuan and power hungry but they represented the best performance you
could get at the time and unlike in the past they were available to the general
consumer now while it's obviously simpler to implement the alternate frame
rendering approach unfortunately led to the micro stuttering that we became
familiar with in the 2010s since each GPU might complete its frame in a
slightly different amount of time the pacing of frame delivery could be all
over the place resulting in impressive benchmarks but a really poor gaming
experience some attempts were made to smooth out frame delivery NVIDIA for
example released a high bandwidth version of the SLI bridge that allowed
the cards to communicate more quickly but it just wasn't able to keep up with
advancements in monitor technology both in terms of resolution and refresh rate
these Niche projects were taking considerable resources from both AMD and
NVIDIA that along with tepid enthusiasm from game developers who really prefer
to Target the lowest common denominator ultimately led to the demise of consumer
multi-GPU it's not that NVIDIA gave up without a fight though they actually
quietly made an attempt to resurrect SLI in the RTX 2000 generation when they
explored checkerboard frame rendering unlike split frame rendering we which
would have both gpus contributing to each displayed frame but would often
have an ugly scene down the middle CFR would divide the frame into small chunks
for each card to render then composite the result into a single image in theory
it could have been the best of all worlds and even avoid NVIDIA having to
specifically optimize a given game for multi-GPU but they ultimately abandoned
it for a few reasons first the processing overhead was significant
which could increase latency and second DirectX 12's explicit multi-GPU model
showed up around that time which handed multi-GPU control over to the game
developer entirely offloading it from the driver which game developers
obviously haven't done anything with but that doesn't mean the multi-GPU dream is
dead and of all people it's Apple
showing us the way you see the M1 series of socs has far more in common with our
Quantum 3D brick than meets the eye have a look at these die shots and you'll see
what I mean we could think of each of these GPU core blocks on the M1 Pro as
similar to the GPU chips on our brick with a fast enough interconnect they can
act as one to render a single output like we see in the M1 Max but then okay
nothing that we're looking at here is really multi-GPU it's just a bigger
single die GPU it's only when we move to the M1 Ultra
that things get really interesting you see the 64 core GPU in the M1 Ultra acts
for all intents and purposes like a single die solution but Apple disclosed
in their launch event that is actually a dual die design that uses a
game-changing packaging solution that they call Ultra Fusion so it's two gpus
acting as one it's SLI but with
absolutely none of the downsides how on Earth did they do it well you see the
problem has always been the interconnect speed see traditionally once you go off
a single die your bandwidth drops dramatically that's why NVIDIA couldn't
achieve vram coherency across multiple cards via their SLI Bridges the links
were just too slow it's also why tricks like split frame or alternate frame
rendering have always been necessary they couldn't just pull together the GPU
resources because the left hand would have no idea what the right hand was
doing in real time but Apple did it and
both AMD and NVIDIA have also talked
publicly about the possibility of future GPU designs that use multiple chiplets
with high-speed interconnects in order to economically scale performance it's
coming back baby but how does this factor in well the thing is back in 1998
the bandwidth requirements for inter-GPU
communication weren't as high so your
Ultra Fusion interface could look a lot more like this
it's really funny isn't it how the more things change the more they stay the
same just like I always do the same segue to our sponsor vessi it's
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video go check out our coverage of the Evans and Sutherlands Sim Fusion 6500
Cube for more multi-GPU Madness that
thing is really cool