While the IT managers of the world stress about Windows 10's buggy mail client, default browser, and dodgy domains, Microsoft's latest and greatest OS is an exciting proposition for the gamer.

Windows 10, if you didn't know, comes with DirectX 12, which promises significant performance increases (particularly for AMD graphics card users) thanks to its new low-level API features. The trouble is there aren't currently any games out there that use DX12. While Nvidia and AMD have both launched new drivers to bring DX12 support to a range of their GPUs offered today, there's not a single DX12 game to play.

3DMark has a neat draw call benchmark that gives us some idea of how much faster DX12 will be, but it's entirely synthetic. One of the first games to actually use DX12 will be StarDock's upcoming RTS Ashes of the Singularity, with an early beta build showing a significant uplift in performance. We were hoping to check out a special benchmark build of the game this week, but sadly it's been pushed back.

In the absence of DirectX 12, though, there are still some other new features in Windows 10 that gamers might find desirable: the ability to stream Xbox One games to your PC, built-in DVR functions for recording gameplay, and a dedicated games store. Our own Sam Machkovech took an in-depth look at those features, and for the most part he came away impressed.

Which finally brings us to the crux of the matter: What about Windows 10 as a platform for gaming? When you strip away DX12 and other new features, is Windows 10 stable enough for gaming? Are there any underlying optimisations that make Windows 10 inherently faster than Windows 7 or 8? Bugs, glitches, and ropy driver support are a common occurrence with the release of a new OS, with the common wisdom being to give it a month or two before jumping in to let those launch bugs iron themselves out.

TEST SYSTEM SPECIFICATIONS OS Windows 8.1, Windows 10 CPU Intel Core i7-5930K (6-core) RAM 32GB Corsair DDR4 at 2800MHz HDD 500GB Samsung 850 Evo SSD Motherboard Asus X99 Deluxe Power Supply Corsair HX1200i Cooling Hydro Series H110i GTX 280mm Liquid Cooler GPU Nvidia GTX 980 Ti, AMD R9 295X2, AMD R9 290X

Fortunately, as we discovered in our testing, most gamers can make the jump to Windows 10 today without issue. Well, so long as they're not trying to play Far Cry 4 with an AMD CrossFire setup, but more on that later.

Methodology

To test whether there's a performance uplift or decline under Windows 10, we benchmarked four taxing games of various ages on Windows 8.1, Windows 10 with the built-in DVR turned off, and Windows 10 with the built-in DVR turned on. Both Windows 8.1 and Windows 10 were installed fresh and run from the same partitioned SSD (in this case a 500GB Samsung 850 Evo), with the latest drivers from AMD and Nvidia installed. Note that this test wasn't about comparing Nvidia performance to AMD's but rather each vendor's individual performance on each OS.

As an aside, this test also marks the debut of the official Ars Technica UK benchmarking test rig. We haven't overclocked it or otherwise tweaked things yet, but we'll have a full feature about our component choices, overclocking, and a video showcasing the build (hope you like case windows!) after Gamescom.

Benchmarks

For the purpose of testing, all games were run at a 3440×1440 resolution (on LG's glorious 21:9 34UC97 monitor) at high or ultra settings. Unlike when reviewing graphics cards, the specific settings here aren't as important. We're looking at the relative performance between two operating systems.









First up are the average frame rates. The good news is that there's basically no difference in performance between playing games on Windows 8.1 and playing games on Windows 10. The slight differences in frame rates, usually one or two frames per second either way, lie well within margins of error.

The exception to this is AMD's R9 295X2, which is a dual-GPU CrossFire card. We saw a 15 percent drop in performance in Bioshock Infinite under Windows 10, while Far Cry 4 suffered from numerous artefacts and glitches before crashing, meaning we were unable to capture any frame rate data. Unfortunately, we didn't have access to a second GTX 980 Ti to test how SLI fares under Windows 10.

While AMD has put out known bugs under the release notes for its Windows 10 driver, neither Bioshock Infinite nor Far Cry 4 are listed. We've let AMD know our findings, but for now, if you want to play Far Cry 4 under Windows 10 with a CrossFire setup, it might be best to hold off on that upgrade.









Looking at the 99th percentile minimum frame rates, once again there's no discernible difference between the operating systems, with nearly all of the results sitting within the margins of error. Good show, Microsoft!

However, Bioshock Infinite threw up another AMD anomaly under Windows 10, this time for the R9 290X. It lost 10 FPS in performance. There's possibly something fishy going on with either the GPU driver and/or the the OS and the game, but we're not confident about what the cause is just yet.









Unfortunately, the 99th percentile minimum frame times (that is, the amount of time time it takes a GPU to render a frame 99 percent of the time) don't shed much light on what's happening with Bioshock Infinite, but the good news is that they're consistent across the OSes. The only exception is Metro Last Light under Windows 10, where the DVR seems to add a few milliseconds to the frame time. It's completely unnoticeable when actually playing the game, with no sign of the dreaded microstutter.

So, I can upgrade then?

Those players eager to upgrade to Microsoft's latest and greatest OS can, for the most part, jump in without worry. Nvidia and AMD's Windows 10 drivers seem to be doing the trick, with no real performance difference compared to the older OS. Suffice it to say, if you're still rocking Windows 7—which is generally anywhere from 5 to 20 percent slower than Windows 8 and 10—it is probably time to finally make the jump.

We only tested a small subset of games, so there may be others out there that cause issues, but this does gives us a good indication of overall performance. There are a few Windows 10 compatibility lists doing the rounds on the Web, so check those out if you're concerned about your favourite game not working. Hopefully the one big snafu we had with CrossFire and Far Cry 4 under Windows 10 will get resolved soon, particularly as that's a relatively recent release.

As for whether you should upgrade to Windows 10, check out Ars' super in-depth review by the one and only Peter Bright, as well as all of our other launch coverage.

Once DirectX 12 games actually start arriving, we'll revisit the topic of gaming on Windows 10. Along with all those delicious low-level API performance gains, there are some big new features that need testing, including the catchily titled "Explicit Multiadapter" feature. That will allow games to tap into the power of multiple GPUs from different vendors for the first time and even pool their graphics memory. Cue excited squeals from the SLI and CrossFire elite.

In addition to a whole bunch of other potentially game-changing (sorry) features, DX12 also adds split frame rendering (SFR), which allows GPUs to share each individual frame rather than having each GPU take it in turns to render whole frames, which can result in far more efficient rendering.