Dear PCSX2 Developers

[pandubz]

My primary system is a Ryzen 9 3950x with dual RTX Titans. Running demanding games such as Ace Combat 04 with everything set to "Full" (such as mipmapping etc) on 8x Native should be completely fine. However, it isn't and I am noticing some noticeable lag. I have tried many presets, including the aggressive one. I have tuned the Nvidia control panel, and given PCSX2 high priority.

Core latency has nothing to do with the picture, and I can assure you Ryzen 3000 series (and upcoming 4000) have zero issues with core-to-core or core-to-gpu latency, especially under a PCIe-4.0 framework. Additionally, my system has 128 GB of DDR4 3666 with extreme tuned low-latency Samsung B-die Ram.

In simplest terms, this has almost nothing to do with your PC and almost everything to do with the PS2 and modern hardware design.

Setting everything to full on purpose is like you driving into a wall at 80 MPH and then being upset that your car is broken and you almost died. Yes. Your car is broken and you almost died. Because you turned every setting up to levels that should never be used for anything except development and debugging the emulator.

Example, Blending Accuracy works at very reasonable levels just on Basic. This still uses the Fixed Unit of your GPU, and does what it needs to reasonably. However, because blending on the PS2 was so fundamentally different from how any modern PC GPU, we have no way to reliably reproduce it just using the Fixed Unit alone. What you are seeing at Full is what happens when you try to accurately reproduce a feature for an old, non-standard rasterizer on a new GPU. It runs entirely on your GPU's shader cores; you have hundreds of these in your GPU but each one is substantially slower than the Fixed Unit, and due to the sheer amount of math it has to do to get close to the original behavior it slows to an absolute crawl.

Your memory usage case is currently the only case for supporting a 64 bit build however there are little to no known cases of PCSX2 using more than 2 GB of RAM at any time. If you do have a case, screenshots of memory use, details about the game, what part of the game, and specific recompiler/speedhack settings would help to know. Video memory can exceed 4 GB easily if internal resolution is turned up, but this has absolutely nothing to do with bitness, and your GPU will be able to address it's full memory space regardless.

If you want 64 bit PCSX2 because you think that will speed it up, turn around and focus your hopes elsewhere because all initial analysis is saying a 64 bit PCSX2 would be slower. The current recompilers are packed full of optimizations that would have to be recreated from the ground up. Most of these optimizations were made by team members who are no longer present in the community and the knowledge of how they work is lost. To match current speeds, we would need to re-learn how these optimizations work and reimplement them in 64 bit instructions. That of course is assuming that they are even possible with a 64 bit instruction set, and that the change of instruction sets does not inherently slow things down (which is the current belief).

The only known benefit of a 64 bit PCSX2 right now is that Linux users will not have to worry about i386 dependencies, since all mainstream Linux distributions are now primarily 64 bit with talks of removing 32 bit libraries in the future. We would like to move forward with this and be ahead of the curve, but it is not as simple as throwing developers at a problem and blinking twice. Someone has to want to do it. This is a community based project, and if no one crazy enough to take on the challenge has the time and knowledge to do it, then it's never going to get done.