Having some trouble with Shaders slowing down the emulation




I have a fairly decent system I think for emulation - it’s a Core 2 Quad with an Nvidia GeForce 8400 GS with 2GB of vram. Everything runs pretty fast and everything is working except this thing with the shaders.

I’m using the GL video driver and dsound audio driver. I’m running the current 205 mame core.

When I activate the crt-easymode shader (glsl) the game slows down to about 20 fps and the audio gets all broken. I’ve tried setting the sound driver to nul thinking maybe sound had something to do with it but the video is still slow. It looks like the shader is applied but everything is just really slow. If I turn the shader off everything goes back to normal.

Don’t even know where to begin to troubleshoot this. Let me know if there are logs I could post although being a performance thing there probably aren’t any errors.



It seems that’s just a very weak GPU, unfortunately. Benchmarks I found online indicate that it’s somewhere between Intel’s integrated HD 3000 (Sandy Bridge) and HD 4000 (Ivy Bridge) graphics.

That said, I would still expect it to be able to push crt-easymode, which is pretty lightweight, well enough. Do you have the MAME core’s “alternate render” core option enabled, by chance? If so, it messes up shaders.


Not that I know of unless it is on by default. I’ve got a pretty vanilla install of RetroArch at the moment… all I’ve done is change the input controls.

If we can tie it down to poor performing GPU I can for sure upgrade that - it was just a cheap card I had laying around and figured for emulation it would do the job.

Where do I check for that option? Is that in the core-options config file? Rich


Just checked and the alternate_renderer is disabled. Can this be seen in the interface somewhere just to confirm that it’s reading the proper config file? Rich


Alright, you’re probably good, then. You can check in the quick menu > options menu. Some other shaders to try would be zfast-crt and crt-pi. If it can’t get either of them full speed, there’s probably something amiss.


Both of those shaders seem to work okay so then it’s probably an issue with that graphics card then? Sounds like I may want a video card a little more powerful… any recommendations on a low profile card that won’t break the bank? Rich


Yeah, sounds like your GPU is just a bit weak.

That really depends on what you’re thinking of as affordable. For $100-150, you can get a radeon 560 or an nvidia 1050, either of which should be a big step up.


Question is do you think the CPU is sufficient? I guess that depends also on what I want to emulate but I was hoping to be able to run Wii games on Dolphin.

I’m considering building a Ryzen 2200g based micro ITX for my cabinet but haven’t quite got the funding for it yet :wink: - mainly just trying to get software all set. Thinking the built in gpu for that would work fairly well.

Thank you so much for your help.


I’m not sure if that CPU is enough for dolphin or not. It’d be borderline at best, I think.

I’ve been thinking of doing a similar Ryzen build, myself, and yeah, the integrated GPUs on those is comparable to a Radeon 7770, which should be plenty.


Watched an ETA Prime video where he built a system with a Ryzen 2200g and it was handling about whatever he wanted to throw at it so figured that would be a pretty good way to go.

I priced it out and looks like I could do it for somewhere around $300 since I don’t need an HDD or case. Helps to have the GPU built in. At that price it’s not worth even messing with this older system.