4K on a budget: the GTX 970 experiment

Can Nvidia's now-discontinued GeForce GTX 970 successfully power a 4K ultra HD display on a range of challenging PC games? On the face of it, the notion sounds ludicrous - on a specs level we're severely constrained by memory capacity, bandwidth and of course, basic compute power. But consider this: the prices of 4K monitors and TVs are dropping like a stone, but relatively speaking, graphics hardware is holding its price. On a general level, we need more from our graphics hardware, and the GTX 970 is an excellent subject for our tests to see just how far mainstream GPUs can be pushed.

The choice of this particular video card is not coincidental. The GTX 970 is a sales phenomenon to the point where even though it was removed from sale some time ago, it's still the second most popular GPU in the Steam hardware survey, just ahead of its effective Pascal replacement, the GTX 1060. Overclock the GTX 970 and as long you're not bogged down by sub-optimal drivers, or held back by its lower memory allocation, its ballpark performance is on par with the 1060. Automatically, our test results here will apply to around 10.5 per cent of the current PC gaming market.

On top of that, it's also a benchmark for extrapolating out the baseline for potential 4K performance on other cards too - GTX 980, R9 390, RX 480 and RX 580, for example. Recently, we ran a feature on the ways that this tier of GPU hardware could produce PS4 Pro-beating performance, if developers embraced the smart rendering techniques Sony and others have pioneered. But these tests are different - ideally, we're looking for console-equivalent performance (or better) at native resolution: true 4K, as Microsoft would put it.

Our initial experiments could only begin by addressing the age-old question: can it run Crysis? More specifically, could we run the entire Crysis trilogy at native 4K on a GTX 970? It's all about reducing the lowest recorded frame-rates here, and the fact is that there's a very large amount of overclocking headroom on all of Nvidia's Maxwell-era graphics cards. Typically, you can add +200MHz to the core and +500MHz to the GDDR5 memory, using a tool like MSI Afterburner. Just remember to ramp up power delivery as far as it will go (110 per cent in the case of the GTX 970) and you're good to go. We've even managed this without issue on a small form-factor Zotac card - just remember to deduct any factory overclock the card may have from that +200MHz. So, in the case of our test subject - an MSI Gaming 4G version of the GTX 970 - we need to dial in +136MHz instead, as it already comes with a 64MHz factory OC.

The original Crysis - the game that has melted untold thousands of gaming rigs during its illustrious career - proved no problem whatsoever. A mixture of the highest settings, with a couple of minor downgrades to the usual culprits (shadows and MSAA, naturally) kept this game in 35-40fps territory, though heavily modded versions of the game may require further tweaking. And by extension, Crysis 2 in DX11 mode - a far richer title visually - also operated in the same ballpark.

Shadows and shading are the key presets to keep an eye on here, but the key takeaway is that tuning the GTX 970 for 4K gameplay isn't about reducing global presets from ultra to high to medium. It's about experimenting with individual settings. There's no need to turn off the highest quality textures in any of the Crysis games - there's ample memory available with the GTX 970. Similarly, Nvidia's Maxwell technology processes geometry like a demon, so reducing object detail as part of a global settings cull only hurts image quality. Typically, you can keep 16x anisotropic filtering, but 8x looks much the same and costs less. At the end of the day, an optimal configuration is actually something akin to console-quality settings on virtually any multi-platform game: there's rarely a single global preset equivalent. Developers choose the best bang for the buck across the entire menu of options available.

OG Crysis still has the edge on gameplay, but Crysis 2 still manages to hold up visually, and looks superb rendered at 4K. Crysis 3? The first half of the campaign is great to play and 4K at 30fps is, by and large, achievable. There are hotspots that still struggle, but again, it is possible to mix and match your presets in the advanced settings to keep gameplay north of 30fps. We ended up with a mixture of very high, high and medium settings and the game still looks beautiful - many of the presets are context sensitive (effects, for example), so dialling those down is good for dealing with minimum frame-rates in fire-fights, but won't compromise the look of the game generally. Crysis 3 is over four years old now but looks simply beautiful at 4K resolution. Dropping to 30fps isn't totally ideal of course, but it also reduces the CPU requirement. Crysis 3 needs an i7 to render at 60fps, but all of the tests in this piece were carried out with a 3.2GHz Core i5 6500.

Nvidia hardware also benefits from the ability to enforce a properly frame-paced 30fps, something that proves elusive on AMD hardware. There are two options here: dip into the GPU control panel and attach half-rate adaptive v-sync to the game's executable. This locks you to 30fps, and drops v-sync if you dip beneath - a similar strategy to many console titles. We'd recommend setting pre-rendered frames here down to one for lower input latency.

An alternative is to use Nvidia Inspector, a third party registry tweaking tool. Here, you can select the frame-rate cap of your choice, and engage triple-buffering, so those dips under 30fps aren't accompanied by tearing as they are with half-rate adaptive v-sync. The only negative point against a PC 30fps lock: control. It's fine with joypad control, but mouse and keyboard doesn't feel good at all.

Buoyed by these respectable results, our next challenge proved even more daunting than taking on the complete Crysis trilogy - we wanted to power through all four of Warner Bros' Batman Arkham titles at native 4K with consistent performance. And yes, we did include Batman Arkham Knight in our tests, reviled as one of the most sub-optimal PC ports to come to market. Perhaps predictable, bearing in mind their years, Arkham Asylum, Arkham City and Arkham Origins proved a cinch to run at full-fat 4K60 - simply disabling PhysX and replacing MSAA with FXAA (either in-game, or via the Nvidia GPU control panel) gets the job done.

Level of detail had to drop down one notch on Arkham City, and DX11 features in City and Origins had to be dialled back - with the exception of DX11 geometry in the latter (this is good news, as dynamic snow deformation was a signature exclusive of the PC version). Art quality across the older Arkham titles varies at 4K - these were games mastered with 720p in mind, remember - but they stand up for the most part, and just a decent high-res texture pack would bring them into contention. But even without, these titles are still attractive. Origins isn't a good tonal match for the other games in the series in terms of art direction, but Rocksteady's focus on owning Unreal Engine 3's signature high frequency detail is a good match for 4K resolution.

And the same applies to Arkham Knight, really. This title is extremely rich in detail, and being a modern title, it has access to higher resolution textures than the console versions. 4K, 30fps is the only real option for this title but with the GTX 970, it's a continuous battle to hold on to the target frame-rate in the game's stress points. Dialling back shadows helps, as does disabling anti-aliasing, but to maintain 30fps - especially in the troublesome Batmobile scenes - well, that's a challenge. In the end, we had to 'cheat' here. We used ToastyX's custom resolution utility to inject two additional resolutions - 3200x1800 and 3456x1944. Games can then render at these pixel-counts, with the GPU upscaling to 4K output.

Our 'hacked in' 1944p preset still wobbles in Batmobile sections, but mostly sticks to the target, while dropping to 1800p allows Arkham Knight to run at maximum settings, even with the Nvidia PhysX options in play (in retrospect, we would recommend disabling the enhanced smoke and fog though, we ran it enabled in the video but further play confirms that it does cause some issues).

Fundamentally, the use of arbitrary resolutions is a great tool for producing decent presentations for ultra HD screens - even if the pixel count is not 'true 4K'. Combine extreme pixel density, the quality of GPU scaling, and LCD's 'sample and hold' motion handling technology (which reduces effective resolution in motion) and scaling up from a sub-native resolution is the solution for stabilising performance and the hit to image quality isn't that pronounced. 1944p represents 90 per cent of native 4K on each axis and is virtually unnoticeable. 1800p looks a touch softer but still looks great on most content.

All of which brings us to our latest and greatest 4K on a budget exercise - Forza Horizon 3 and Forza Motorsport 6 Apex. All of our tests to date have yielded some impressive results, but it's always been a struggle to tune these challenging games for consistent, optimal frame-rates - after all, true 4K resolution is four times the resolution of 1080p, the GTX 970's traditional stomping ground. Some of the cuts we make to image quality feel deep - but playable frame-rates must take priority and in adjusting our settings, inevitably you end up optimising around worst-case scenarios. In short, you are cutting down on image quality all of the time, when in reality, you only need to do so some of the time. And this is what sets PC's Forza titles apart from the pack.

You can achieve simply sensational results from both games here simply by selecting high settings and engaging dynamic optimisation. For Forza Horizon 3, the 30fps cap needs to be enabled for the best, most consistent gameplay experience, but Forza Motorsport 6 Apex runs almost flawlessly at full-fat 60fps. And it's glorious, simply sensational. The game itself is balancing GPU load for you on the fly, essentially tweaking your settings for you as you play, always prioritising frame-rate, but making nips and tucks to quality settings in the most unobtrusive manner possible. We noted some obvious car LOD popping on Apex in the most busy scenes, but beyond that, the presentation holds up.

On top of that, image quality is off the charts. Both titles not only lock resolution at the full 3840x2160, but remarkably, there's overhead left over for multi-sampling anti-aliasing (and FXAA in Forza Horizon 3). We actually had issues engaging full anisotropic filtering in Apex, but this is easily solved with a trip to the GPU control panel, where it can be forced to the max at the driver level. Bearing in mind how tightly Turn 10 optimises for Xbox One and how good the dynamic settings scaling is, we can't help but wonder whether its upcoming Forza Motorsport 7 will run at similar, buttery-smooth frame-rates at true 4K on GTX 970. Full 4K textures are almost certainly off the menu, but regardless, we'll be fascinated to give it a go. Certainly, the technique of adjusting quality settings on the fly rather than employing dynamic resolution is a fascinating idea - and it's a brilliant technical feat bearing in mind just how solid frame-rates are.

We'll continue these tests on the Digital Foundry YouTube channel, so consider subscribing for further 4K on a budget episodes. While we've been pushing the envelope with advanced titles, we were actually inspired to start the series by our very own John Linneman, who upgraded to an LG OLED 4K TV before the launch of PS4 Pro last year, and promptly found that the GTX 970 was his only potential route to 4K gaming. He recommends a wealth of older games that hold up beautifully at native 4K, given a new lease of life by the move to extreme resolution. He recommends titles including Sonic Generations, Criterion's Need for Speed releases, Castlevania: Lord of Shadow and the BioShock 1/2 remasters, for starters - most of which operate at 60fps. And these choices also serve to highlight a unique strength of the PC platform - the ability to scale will obviously vary according to each game, but potentially any older title in your library already has a 4K 'remaster' available for play, and not every game requires an Nvidia Titan or Ti product to achieve beautiful results.

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