Just a question about how PCSX2 deals with 30 fps games

[Bjoolz]

With the release of FFX/X-2 HD remaster on steam I noticed it was capped at 30fps. I had played this a few times with PCSX2 and I was sure it was running at 50 (PAL). And sure enough, PCSX2 states it is running at 50 fps. So I set up FRAPS to record it at 50 fps and skipped forwards one frame at a time. Every frame was duplicated once, so the PAL version was actually running at 25 fps (Which makes sense if it's a 30 fps NTSC title, NTSC = 60/2, PAL 50/2).

Now to the question. Does PCSX2 render each frame twice (Does that make it double the work load? I guess that's another question) or is the FPS display just a raw conversion of game speed? For example, if the game runs at 100% it displays 50/60 fps no matter what the frame rate is and if it runs at 80% it just calculates that 80% of 60 is 48, again without actually measuring the frame rate.

This is just something that popped into my mind and I got really curious.  I'm not savvy enough to know how to check it myself

[ssakash]

Does PCSX2 render each frame twice (Does that make it double the work load? I guess that's another question)

In Interlaced mode, yes. It only needs half the bandwidth required for progressive scan mode so no extra workload.

is the FPS display just a raw conversion of game speed?

It's the no.of VSyncs per second (AKA VSync rate) , not the frames pushed per second.

[gregory]

Technically all games are 50/60fps but most of them present each frames 2 times (so real speed is 25/30fps). So rendering is done once, but post-processing/merge/present is done twice. It explains why it doesn't play well with low power feature. You have a peak of activity for the first image and then a near empty image.

[Bjoolz]

Thank you to both ssakash and gregory!