Nvidia Optimus allows us to get better battery life out of a laptop by using the Intel graphics,
but just how much gaming performance is it costing us, and can we improve it? In this
video we’ll see the performance differences in different games with and without Nvidia
G-Sync enabled, and find out if we can boost performance by using an external monitor to
bypass Optimus.
Just as a refresher, Nvidia Optimus is present in most laptops these days. Basically it allows
the Intel integrated graphics to do the work outside of graphically intensive tasks like
gaming, allowing the battery to last longer, as the Intel integrated graphics are less
powerful. When you open up a game though, it’s smart enough to start using the discrete
Nvidia graphics.
In order to do this, the Nvidia graphics renders the game, however the result still needs to
go via the Intel graphics as that’s what’s sending the signal out to the display, and
it’s this which in turn creates an overhead and can reduce gaming performance, it’s
an extra step in the process.
Nvidia’s G-Sync is an adaptive sync technology which essentially removes screen tearing,
resulting in a smoother gaming experience. In order to do this though, the laptop’s
display needs to be connected directly to the Nvidia graphics. This is why you lose
the benefits of Optimus with G-Sync enabled, with G-Sync enabled the more powerful Nvidia
graphics will be in use the whole time even when you’re not gaming, resulting in worse
battery life.
Many laptops these days, like the ASUS Zephyrus GX701 I recently tested, give you the option
of swapping between the two. Changing requires a system reboot though, so it can be inconvenient
to switch but at least you have the option if you want it. Just for reference here’s
what we’re looking at in terms of battery life with the GX701 with and without G-Sync
disabled. In gaming there’s no difference, however outside of gaming and just watching
YouTube we’re getting much longer battery life in Optimus mode as it’s more power
efficient. While testing the GX701 I was getting substantially
better frame rates with G-Sync enabled. I’ll also note that some laptops don’t have either
Optimus or G-Sync, but still have the display connected directly to the Nvidia graphics,
in theory these should perform better in games too. G-Sync isn’t a requirement, it’s
just that G-Sync requires the direct connection between GPU and screen. Let’s look at some
resource usage examples to get an understanding of what’s happening.
Here’s what it looks like while playing Watch Dogs 2 with Optimus enabled, we can
see the CPU is maxed out at 100% in this game, while the 2080 Max-Q graphics are around 50%.
The Intel integrated graphics are around 25%, because the Nvidia graphics are passing the
output through here to display on the screen, essentially adding extra overhead. Now here’s
the same test but with G-Sync enabled. We can see that the utilization of the 2080 Max-Q
graphics is a fair bit higher now, closer to the 80% range as it’s not being bottlenecked
by the Intel graphics.
Let’s take a look at how much of a difference this makes to performance. I’ve tested 15
games with the same Nvidia drivers, game and Windows updates installed. The only differences
are that G-Sync has been enabled or disabled.
Let’s start with Watch Dogs 2, given it’s the game I was tested with earlier. I’ve
got the frame rates with G-Sync enabled in the top bar, with the Optimus results on the
bottom. We can see straight away there is a fair improvement in this game with G-Sync
enabled, over 20% higher average FPS.
Overwatch was tested in the practice range, as it allows me to perform exactly the same
test run each time. Again there was clearly an improvement with G-Sync enabled, which
was averaging 15% higher average FPS when compared to Optimus. Perhaps more importantly
is the massive 42% boost to 1% low with G-Sync.
The Witcher 3 is our first example that shows some games don’t really seem to change,
we’re getting basically the same results here regardless of having G-Sync enabled or
using Optimus, with just a small 1.1% boost to average FPS with G-Sync enabled.
Metro Exodus is another such game and was tested with the built in benchmark, we’re
only seeing within one to two percent improvements to average FPS with G-Sync enabled, regardless
of whether or not we have ray tracing enabled. The RTX results are in red, while the purple
result shows the extreme setting preset.
Battlefield 5 saw a small 1.3% improvement with RTX off in the purple bar with G-Sync
enabled, though the 1% low was actually a little lower. With RTX on in the red bar,
it was actually performing better with Optimus enabled, so I’m guessing this may be something
specifically related to RTX, as this was the only result to see worse performance with
G-Sync enabled.
Shadow of the Tomb Raider was tested with the built in benchmark, and G-Sync was giving
a 9.5% higher average frame rate in this test compared to using Optimus.
Shadow of War was also tested with the built in benchmark, and was another where the difference
was much smaller, with just a 2% boost to average FPS with G-Sync enabled.
Assassin’s Creed Odyssey was also tested with the built in benchmark, and this game
saw one of the largest results out of all games tested. There was a 25% improvement
to average frame rate in this test once G-Sync was enabled.
Rainbow Six Siege also saw a big boost with G-Sync enabled, averaging 23% higher average
FPS in the built in benchmark at ultra settings.
I tested PUBG with the replay feature at ultra settings, so the exact same replay was used,
and there was a 17% boost to average FPS with G-Sync enabled in this game.
Ghost Recon was tested with the built in benchmark, and there was still a fair improvement of
7% to average FPS here with G-Sync enabled, and a larger 20% improvement to 1% low performance.
CS:GO was tested with the ulletical FPS benchmark, and this game saw an insane improvement with
G-Sync enabled, with 85% higher average FPS.
Dota 2 was tested playing in the middle lane with an average amount of action going on,
and this test also saw a big improvement with G-Sync enabled, with 39% higher average FPS
when compared to the Optimus result.
Far Cry New Dawn was tested with the built in benchmark, and there was a nice 13% boost
to average FPS with G-Sync enabled.
Far Cry 5 was also tested with the built in benchmark, and a little smaller 7% improvement
to average FPS in this test with G-Sync in use.
In terms of overall improvement, over all 17 game comparisons with a 1080p resolution
at max settings on average there was a 15.3% higher average frame rate with G-Sync enabled
compared to using Optimus. As we can see it very much so depends on the game, CS:GO was
seeing an insane boost with G-Sync enabled while I actually saw worse performance in
Battlefield 5 with RTX off. Despite these outliers, there was a clear performance improvement
in most games with G-Sync enabled.
That’s great, but what can you do if your laptop doesn’t have G-Sync?
As most laptops also have display outputs such as HDMI or mini DisplayPort wired to
the Nvidia graphics rather than the Intel graphics, you can also improve performance
simply by plugging in an external monitor. The laptops display will be going through
the Intel graphics if it’s using Nvidia Optimus, and will therefore by subject to
the additional overhead, however connecting an external monitor bypasses this process
as the Nvidia graphics can now output the signal directly to the external screen. Some
laptops may have the outputs connected to the Intel graphics, it varies by machine.
I’ve tested an external monitor compared to the laptop’s screen with the Dell G5
in three games. It’s got RTX 2060 graphics and no option of G-Sync, so all games run
with Nvidia Optimus by default with the laptop screen, so let’s compare with and without
an external monitor.
In Shadow of the Tomb Raider I’ve tested again with the built in benchmark, and with
the external monitor at maximum settings there was a fairly decent 11% improvement to average
FPS.
Assassin’s Creed Odyssey was also tested with the built in benchmark at maximum settings,
where there was again an 11% boost to average FPS with the external monitor plugged in.
Finally I’ve just tested The Witcher 3, and if you recall from the G-Sync test earlier
there was almost no difference, and that seems to be the case here, just confirming that
it varies by game.
This shows that we can improve performance to any laptop using Nvidia Optimus, so long
as it has external display outputs that are hooked up to the Nvidia graphics, some may
be connected to the Intel graphics and would be useless for gaming, it depends on the laptop.
Granted most people probably won’t be plugging in a monitor to the laptop, the whole point
is portability, but if you’re docked at the office or at home and have space for a
larger monitor you’ve got the option of boosting performance a little.
The principle is the same as enabling G-Sync in the GX701, using an external monitor ensures
that we don’t get performance overhead from the Intel graphics in the same way that using
G-Sync does, and both methods can be used to improve game performance at the expense
of less battery life. G-Sync does of course also give us the benefit of variable refresh
rate, removing screen tearing, so if you’re primarily using your laptop while plugged
into the power anyway leaving G-Sync enabled will result in both smoother game play, but
as we’ve seen here also increased levels of performance as a side effect of G-Sync
is requiring that direct connection between the GPU and display.
I’m also not too sure how much the performance difference varies based on different graphics
cards, as I don’t currently have any other G-Sync laptops available, but I’m thinking
it would differ based on the GPU power, so different results should be expected.
So which sort of laptop should you get? There are basically three choices, the most common
is a laptop with Optimus, you get the key benefits of more battery life outside of gaming
but also the ability to use the Nvidia graphics when you open up a game. This is honestly
probably the best option for most people, best of both worlds. There are also some laptops
that don’t have G-Sync, but have the display connected directly to the Nvidia graphics.
These don’t use the Intel graphics at all, so burn through battery power faster, however
in theory they should perform better in games when compared with an optimus solution. These
may have G-Sync, it depends on the laptop, but you can have the direct connection without
G-Sync, it’s just that G-Sync requires this to function. The third option would be laptops
that allow you to swap between G-Sync and Optimus with a reboot like the GX701, granted
a reboot is a bit of a pain if you swap regularly, but it does give you the choice which mode
you run the machine in.
Let me know which option you’d pick down in the comments, and if you’re after more
information on the details of Optimus you can find a link to Nvidia’s white paper
linked in the description, and as always don’t forget to subscribe for future tech videos
like this one.