2 ways to increase gaming performance by up to 75% on an old PC

Luke Larsen / Digital Trends

Even if your PC is getting old, that doesn’t mean playing the latest games is impossible. While some performance-boosting features were previously reserved for those with one of the best GPUs or one of the best processors, now modders have stepped in to change that narrative.

As a result, the mod allows the use of Nvidia’s DLSS 3 (or more precisely, AMD’s FSR 3) on much older graphics cards. Confusing? Don’t worry, it makes a lot more sense than it seems, and you can use it to increase your PC’s gaming performance by up to 75%.

DLSS is Nvidia’s game-changing frame generation technology. At least on paper, it’s locked to RTX 40 series graphics cards. AMD’s FSR 3 is a counterpart to Nvidia’s DLSS 3, and is open-source, meaning it’s available on more graphics cards than Nvidia’s proprietary technology. On the surface, you might think that this means frame building should be available to many gamers, but that’s not the case. This is because adoption of FSR 3 is very slow and until now it is only available in four games.

However, Digital Foundry recently discovered a mod that works with all games that support DLSS 3 natively. This mod essentially tricks the computer into believing it is running an RTX 40 series card, but can actually be used on older RTX GPUs (20 and 30 series). The trick is that it doesn’t run DLSS 3; instead, it enables the open source FSR 3 which works on many graphics cards.

Basically, this allows you to run games with FSR 3 that won’t run, not because of GPU limitations, but because the feature isn’t available in that title. The funny part? This doesn’t work on AMD GPUs.

Using DLSS 3 mod with FSR 3.
Digital Casting

Running the mod requires inserting the DLL file into the game directory, editing the registry, and finally, enabling the feature in the game. All that makes this FSR 3 masquerading as DLSS 3 work, and according to Digital Foundry, it looks pretty brilliant.

Tested the mod with some AAA games, such as Cyberpunk 2077, showing a tremendous performance increase over the RTX 3080. When the mod was run, the RTX 3080 was able to maintain over 100 frames per second (fps) at 1440p in RT overdrive mode; without it, speeds reached a much more impressive 60 to 70 fps. This marks an improvement of up to 67% at 1440p. Spider-Man: Miles Morales saw even greater improvements, with increases of up to 75%.

Unfortunately, running this DLSS 3-slash-FSR 3 merge results in several drawbacks, including visual artifacts and higher latency. This issue has been largely addressed in games that support FSR 3, but considering this is just a mod, it’s not surprising that it’s not perfect. Check Digital Casting Video if you want to learn more about the mod and potentially try it yourself.

Nvidia Resizable Bar Illustration.

Turning your old Nvidia GPU into a container for AMD’s FSR isn’t the only thing you can do to get extra frame rates. PC Gamer recently dug up an interesting GitHub project called RenewUEFI, which is a BIOS mod that allows you to run Resizable BAR (ReBAR) on older PCs from 2011 that don’t support it. ReBAR is a feature that allows your CPU to access the GPU’s full frame buffer instead of being limited to just 256MB, as is the case on hardware that doesn’t support it.

Older motherboards often don’t support Resizable BAR, but mods let you bypass this limitation and run with it. ReBarUEFI adds settings in the BIOS on older motherboards, allowing the CPU and GPU to communicate effectively. This means a performance increase of up to 12%, according to the mod’s author, and perhaps even more on Intel Arc GPUs, as they require ReBAR.

While the DLSS 3 mod seems easy enough to enable, ReBarUEFI is a little more complicated. If you really want to try it, we recommend reading the instructions carefully and accepting the idea that something might go wrong — and if something goes wrong in the BIOS, your entire PC might be affected.

Whatever the choice, it’s great to see people finding ways to bring new technology to old PCs, even if it takes some tweaking to make it work.

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