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Forza Motorsport 7 Performance Preview - Vega vs Pascal

Forza Motorsport 7 Performance

The first full Forza Motorsport title available for the PC, Forza Motorsport 7 on Windows 10 launched simultaneously with the Xbox version earlier this month. With native 4K assets, HDR support, and new visual features like fully dynamic weather, this title is an excellent showcase of what modern PC hardware can do.

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Now that both AMD and NVIDIA have released drivers optimized for Forza 7, we've taken an opportunity to measure performance across an array of different GPUs. After some significant performance mishaps with last year's Forza Horizon 3 at launch on PC, we are excited to see if Forza Motorsport 7 brings any much-needed improvements. 

For this testing, we used our standard GPU testbed, including an 8-core Haswell-E processor and plenty of memory and storage.

  PC Perspective GPU Testbed
Processor Intel Core i7-5960X Haswell-E
Motherboard ASUS Rampage V Extreme X99
Memory G.Skill Ripjaws 16GB DDR4-3200
Storage OCZ Agility 4 256GB (OS)
Adata SP610 500GB (games)
Power Supply Corsair AX1500i 1500 watt
OS Windows 10 x64 
Drivers AMD: 17.10.1 (Beta)
NVIDIA: 387.92

As with a lot of modern console-first titles, Forza 7 defaults to "Dynamic" image quality settings. This means that the game engine is supposed to find the best image settings for your hardware automatically, and dynamically adjust them so that you hit a target frame rate (adjustable between 30 and 60fps) no matter what is going on in the current scene that is being rendered.

While this is a good strategy for consoles, and even for casual PC gamers, it poses a problem for us trying to measure equivalent performance across GPUs. Luckily the developers of Forza Motorsport 7, Turn 10 Studios, still let you disable the dynamic control and configure the image quality settings as you desire.

One quirk however though is that in order for V-Sync to be disabled, the rendering resolution within the game must match the native resolution of your monitor. This means that if you are running 2560x1440 on your 4K monitor, you must first set the resolution within windows to 2560x1440 in order to run the game in V-Sync off mode.

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We did our testing with an array of three different resolutions (1080p, 1440p, and 4K) at maximum image quality settings. We tested both AMD and NVIDIA graphics cards in similar price and performance segments. The built-in benchmark mode for this game was used, which does feature some variance due to dynamic weather patterns. However, our testing within the full game matched the results of the benchmark mode closely, so we used it for our final results.

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Right off the bat, I have been impressed at how well optimized Forza Motorsport 7 seems to be on the PC. Compared to the unoptimized disaster that was Forza Horizon 3 when it launched on PC last year, it's clear that Turn 10 Studios and Microsoft have come a long way.

Even gamers looking to play on a 4K display at 60Hz can seemingly get away with the cheaper, and more mainstream GPUs such as the RX 580 or the GTX 1060 with acceptable performance in most scenarios.

Games on high-refresh-rate displays don't appear to have the same luxury. If you want to game at a resolution such as 2560x1440 at a full 144Hz, neither the RX Vega 64 or GTX 1080 will do this with maximum image quality settings. Although these GPUs appear to be in the margin where you could turn down a few settings to achieve your full refresh rate.

For some reason, the RX Vega cards didn't seem to show any scaling in performance when moving from 2560x1440 to 1920x1080, unlike the Polaris-based RX 580 and the NVIDIA options. We aren't quite sure of the cause of this and have reached out to AMD for clarification.

As far as frame times are concerned, we also gathered some data with our Frame Rating capture analysis system

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Taking a look at the first chart, we can see while the GTX 1080 frame times are extremely consistent, the RX Vega 64 shows some additional variance.

However, the frame time variance chart shows that over 95% of the frame times of the RX Vega 64 come in at under 2ms of variance, which will still provide a smooth gameplay experience in most scenarios. This matches with our experience while playing on both AMD and NVIDIA hardware where we saw no major issues with gameplay smoothness.

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Forza Motorsport 7 seems to be a great addition to the PC gaming world (if you don't mind using the Microsoft store exclusively) and will run great on a wide array of hardware. Whether or not you have a NVIDIA or AMD GPU, you should be able to enjoy this fantastic racing simulator. 


October 24, 2017 | 07:15 PM - Posted by Pascalega (not verified)

That 1080 frame times! :-O

(jaw drop)

Suggestion: it appears to me that the large spikes in the beginning of the plot are due to the level starting. Perhaps cut these out from the variance plot because they are a one time event and not indicative of game play?

October 25, 2017 | 12:20 PM - Posted by Ken Addison

You are likely correct about the frame time spike, but racing games go between events fairly often during a gameplay session, so loading of assets is definitely a reality. 

October 25, 2017 | 07:45 PM - Posted by peter j connell (not verified)

"... likely correct about the frame time spike, but racing games go between events fairly often during a gameplay session, so loading of assets is definitely a reality. "

Meaning what exactly. Is it reading fresh scenes~ from disk?

The important point i am leading to, is that tho gamers dont seem to realise or discuss it, I feel raid nvme storage has a future role in better gaming, yet gamers are so focused on a few fps here and there, they are blithely buying intel cpuS w/o the required lanes for nvme arrays. 16 lane rigs are a complete dead end, and most intel gaming rigs are.

The am4 ryzens are 20 lanes. Not great either, but the extra 4 lanes makes a big difference.

I see modern games that "load" 68GB. Clearly too big for gpu or system ram, and its a millstone to game play if read from disk during play.

The media speed hierarchy is:

hundreds of GB/s internally on the gpu ram bus

Subject to the gpu link to the pc being 16GB/s, its about 25GB/s on dual channel am4 & ~40GB/s on 4 channel TR? ie, system memory is max 16GB/s to the gpu via the pcie3 link.

~3200MB/s read & ~2100MB/s write on good single nvme ssd.

500MB/s read on sata ssd

~100MB/s and ghastly access times on sata 3 HDD's.

Clearly there is a huge speed gap between anything capacious enough to hold the 68GB "load" and internal gpu actual gaming speeds.

An nvme raid storage resource on TR however, allows perfect multiples of nvme read speeds, and huge improvements to less relevant write speeds.

Affordable samsung evo 256GB nvme ssdS are ~$140US. On most x399 TR mobos, 3x nvme ports are included, so for $460, gamers can add a 750GB resource w/ ~9GB/s read & ~6GB/s write.

System memory, teamed with this resource, should keep the 16GB/s link to the gpu pretty saturated.

Some vegaS even provide for nvme arrays which bypass the pcie3 link altogether, by mounting it direct to the gpu Fabric bus.

October 24, 2017 | 08:13 PM - Posted by remc86007

"For some reason, the RX Vega cards didn't seem to show any scaling in performance when moving from 2560x1440 to 1920x1080, unlike the Polaris-based RX 580 and the NVIDIA options. We aren't quite sure of the cause of this and have reached out to AMD for clarification."

What is there to clarify? The Vega parts are clearly hitting a cpu bottleneck.

October 24, 2017 | 11:00 PM - Posted by Esch88 (not verified)

cpu bottleneck on a i7-5960X processor? ok then lol

October 24, 2017 | 11:15 PM - Posted by arbiter

Its probably something more related to driver since you look at nvidia and it has scaling in performance at same rez so your claim of cpu bottleneck kinda falls apart there.

October 25, 2017 | 11:17 PM - Posted by remc86007

How so? The driver runs on the CPU. Nvidia may have a more efficient driver and produce more frames on a given cpu, hence the continued scaling.

October 25, 2017 | 01:41 AM - Posted by throAU (not verified)

Maybe not a CPU bottleneck, but an engine bottleneck.

October 25, 2017 | 04:38 AM - Posted by Martin (not verified)

Based on what I see from Forza 7 demo, it is running two threades pegged at 100%, with rest of the threads being used far less. Should be easy enough to get this game CPU limited.

Previously the Vega64 beating 1080Ti that made news had the same problem for Nvidia cards with older Nvidia drivers, less restrictive but still clear CPU bottlenecking at 1080p and even 1440p.

October 25, 2017 | 02:51 PM - Posted by Power (not verified)

Is the RX 580 4GB or 8GB?

October 25, 2017 | 03:33 PM - Posted by Ken Addison

Ah, I forgot to include that. It's the 8GB model.

October 25, 2017 | 05:23 PM - Posted by ermo (not verified)

@Ken:

Your Vega 64 AC is throttling (it shouldn't sit at 1247 MHz).

For your own curiosity, try creating a custom wattman profile where you set the both voltages to 1060 mV, both GPU frequencies to 1600 Mhz, the RAM to 1000 MHz (up from 945 MHz), the fan speed to 400-2900 RPM and the power target to +25% and monitor the GPU speed and voltage during that benchmark using GPU-Z.

This will use around 250W of power, which is the same as the "performance" preset, but it will throttle much less and likely stay above 1500 MHz with the fan running at full tilt.

Adding an extra 250 MHz to the core all the time should result in a linear increase of the performance of 1500/1250 = 6/5 = +20% which is nothing to sneeze at -- and you might find that the frame time variance drops due to the chip no longer throttling.

October 25, 2017 | 07:51 PM - Posted by arbiter

Thing is that would kinda * off the test since this is how the card/driver is acting of its own accord. If it does that slow mhz of its own, doing a modified profile would invalidate the test as you would have to do same for nvidia card but problem with doing that in general is not all cards will get same results from those custom settings due to differences in silicon. Sounds like AMD should figure out what is wrong inside driver and fix it so test can be rerun.

edit: as i looked it up listed base clock of a vega 64 is "1274 MHz". So that is what they listed as that, it could went higher then that we don't know but they list the nvidia card using same ideology using base clock. In all likely hood it ran at higher clocks but they just listed that as its base spec's.

October 26, 2017 | 04:04 PM - Posted by clust3rsekt0r (not verified)

I think you came late to the party I don't know where you get those numbers this game has been benchmark already and your numbers are totally different for what everyone has even your frame times does not have sense at all.

https://www.computerbase.de/2017-09/forza-7-benchmark/2/#diagramm-forza-...

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