Players of "Fallout 4" and "Fallout 76" will not enjoy one of the key benefits of Xbox's new FPS Boost feature, despite other Bethesda titles getting a full upgrade.

FPS Boost was introduced last month, providing a frame rate boost to 60fps for some older Xbox games on the Xbox Series X and Xbox Series S.

The new feature will allow players to upgrade to 60fps on the Xbox Series X and Xbox Series S.

While FPS Boost instantly unlocks 4K 60fps on games like Skyrim, Digital Foundry's testing found that the frame rate boost is only available at 1080p on Fallout 4 and Fallout 76.

This is unfortunate for "Fallout" fans, who will have to choose between turning on FPS Boost and making do with 1080p graphics or turning it off and enjoying 4K.

What is really surprising is that this restriction applies not only to the Series S, but also to the Xbox Series X. The latter console is the smaller and less powerful of the two next-generation Xboxes and is only designed to reach a maximum resolution of 2160, so 1080p@60fps is reasonable. The Xbox Series X, however, is much more powerful and should have no problem handling these specs. [However, as Digital Foundry points out in their test video, "Fallout 4" was a very taxing game on the previous generation consoles.

Fortunately, there are several workarounds. First, there is a Fallout 4 mod called "720p 60fps," which (quite confusingly) unlocks 4K 60fps. The drawback is that while 90-95 percent of the game runs at 60fps, according to Digital Foundry's research, the frame rate drops quite significantly at certain load points.

There is also a way to trick the Xbox Series X into running the game at 4K 60fps without mods: load Fallout 4 without FPS Boost enabled, exit and enable it in the dashboard, and then use Quick Resume to return to the game You will need to exit and enable it in the dashboard and then return to the game using Quick Resume.

For Fallout 76, where 720p 60fps mods are not available due to the online game, a hack must be used: start the game without FPS Boost, exit and turn it on, quick resume another game, and jump back to Fallout 76. Unfortunately, according to Digital Foundry, Fallout 76 has difficulty running at 4K 60fps, usually peaking around 50fps. But perhaps until this trick is patched, it's worth a try.

Sadly, neither the PS5 nor the Xbox One X have these features. So if you want to try FPS Boost for yourself, you will need to purchase an Xbox Series X or S-Series.