perhaps the best example of what full RT
can do comes in the form of Minecraft,
which normally runs on everything
including your old and moldy potato PC
sitting in the corner.
Nvidia says the enhanced version of the
game implements full path tracing, which
isn’t entirely correct, but it does radically
alter the visuals with a detailed lighting
model that handles reflections, indirect
lighting, and more. It also destroys
performance, often taking a game that
can easily render at hundreds of frames
per second without ray tracing down into
the sub-60 and even sub-30 range. And
that’s all for the same base blocky world—
getting all of those effects rendering
in a more complex game at acceptable
framerates simply isn’t possible on
today’s hardware.
Not surprisingly, since Nvidia was
the first out of the gate with ray tracing
hardware by over two years, the various
RTX GPUs rank at the top of our ray tracing
charts. We’re using our “medium” ray
tracing settings for the overall standings,
which puts Nvidia’s top RTX 3090 Ti 50percent ahead of AMD’s top RX 6900 XT.
Meanwhile, the slowest ray tracing card
so far, AMD’s RX 6500 XT, failed to run one
of the games (Control wants at least 6GB
VRAM or you can’t even try to enable ray
tracing), and couldn’t even break 20fps
in the remaining games, with Cyberpunk
2077 and Bright Memory Infinite both well
into the single digits. We suspect Intel’s
lowest-tier Arc offerings might be slower
than the 6500 XT (see Intel Arc sidebar).
Cranking the settings to maximum
proves too much for many of the GPUs,
but Nvidia’s lead grows to 66 percent
at 1080p ultra and 75 percent at 1440p
“ultra”—at which point, even the RTX 3090
Ti just barely clears 60fps average across
our six-game suite, with half of the games
falling below 50 fps. At 4K ultra, the only
way to achieve playable performance is
with some form of upscaling like DLSS;
native 4K averaged just 29fps across our
suite on the 3090 Ti, and half the games
were in the low 20s.
AMD’s entry into the ray-tracing space
more or less lines up with Nvidia’s first-
generation RTX cards. The RX 6900 XTAll our testing has focused
on desktop graphics cards. It
allows us to test the various
GPUs while keeping all other
hardware constant, but there
are also mobile variants
of most graphics cards.
As you can guess, packing
something like a 450W RTX
3090 Ti into a laptop just
isn’t going to happen, not
without drastically cutting
the power use. That results in
the latest mobile GPUs from
Nvidia and AMD generally
being at least one step down
in performance from their
desktop counterparts.
Take the mobile RTX 3080,
for example. It uses the GA104
chip, whereas the desktop
3080 uses GA102. It also has
8GB of memory on a 256-bit
bus instead of 10GB on a 320-
bit interface and comes with
48 SMs and 6144 CUDA cores
compared to 68 SMs and 8704
CUDA cores. It typically runs at
lower clocks as well. All those
cuts are done to keep power
consumption under control,
and the resulting GPU can be
configured to run at 80–150W,depending on the specific
laptop and configuration,
compared to the base 320W of
the desktop 3080.
It’s a similar story for
AMD. The RX 6800M uses the
smaller Navi 22 and has 40
CUs and 2560 shader cores,
with 12GB of VRAM and
TGP (Total Graphics Power)
starting at 145W. The desktop
RX 6800 uses Navi 21 with60 CUs, 3840 shaders, 16GB
of memory, and a 250W TGP.
The specifics of the various
graphics chips over the years
may vary, but the net result is
the same: lower performance.
The 150W mobile RTX 3080,
for example, comes close to
the level of a desktop RTX
3070, while the lower limit
80W configuration will often
fall behind the desktop RTX3060 Ti. AMD’s RX 6800M
likewise falls behind the
desktop RX 6700 XT.
The benefit, naturally, is
that you don’t fry your nether
regions when gaming on
the go, though battery life
still tends to be far less than
two hours for anything that
really uses the GPU—no, a
text-based Zork reimagining
doesn’t count.WHAT ABOUT LAPTOP GPUs?
Many use laptops
for gaming and
computing, but going
mobile means giving
up some performance.delivers nearly identical performance to
the Titan RTX, and the RX 6600 comes in
slightly behind the RTX 2060. Nvidia didn’t
even try for budget RT hardware the first
time round, and poor Navi 24 shows why.
Meanwhile, Ampere’s second-generation
RT hardware is about 75 percent faster
than the Turing RT cores, though the RTX
3050 still ends up being slower than the
RTX 2060.state of the GPUnion address
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