I've got what I hope is a fairly quick question. I've recorded a bunch of footage with my SNES and Super Game Boy, but of course, it runs slightly faster than it should. I don't mind slowing down the footage after recording it, but I'm unsure as to what percentage I need to slow it down by. I recorded it with a PAL SNES (unmodded, at least at the time). I've seen a couple of reports that the PAL SNES and SGB runs only 1.477% faster, as opposed to the 2.4% faster speed from an NTSC machine. However, I can't confirm whether or not this is true. Although it is tricky, I've tried playing an actual Game Boy alongside the footage, and the footage seems to get a bit out of sync eventually, but it could be the imprecise nature of this testing method that caused that instead. So basically, can someone please confirm how fast a PAL SNES+SGB runs above normal? I want the exact number, with every decimal known to mankind, just so I can re-time the footage I've recorded to be the right speed. Oh, also, for the future, will the speed fix for the PAL SGB require a different oscillator to the NTSC one, or is it only the SNES that makes the difference and therefore will run fine as long as the SNES is in NTSC mode?
The clock speed of the GB is 4.194304 MHz. The SGB takes the clock signal from the SNES and divides it by 5. For PAL that is 21.28137 / 5 = 4.256274 MHz so it runs 1.477479935% faster. For NTSC it is 21.47727 / 5 = 4.295454 MHz so it runs 2.411603928% faster. With the speed fix the SGB uses its own clock signal instead of the clock signal from the SNES so the speed should be the same on both PAL and NTSC consoles.
Is there and SGB compatibility issues because of the faster speed? Would the speed fix mod make those games work if the issue is related to speed?
Thanks for your reply. That's really helpful information. I probably could have got it if I dug some more, but with a quick search, the main source of information I could find was Wikipedia which didn't have the exact numbers that you provided. The one thing I'm confused about is the speed fix, though. You said the SGB uses its own clock signal, but that it takes the clock signal from the SNES (and divides it by five, of course). I don't understand, then, how the speed fix would remain constant between PAL and NTSC if it takes the clock signal from the SNES. I'm sure I'm just missing something in the way it functions. Oh, also, just to double-check, and if my mathematics skills aren't totally useless, I'd be decreasing my video to 95.80569600001271454515% correct? 4.256274 ÷ 101.477479935 = 0.04194303999987285454853, x 100 = 4.194303999987285454853; 100 - 4.194303999987285454853 = 95.80569600001271454515. I assume that's accurate. If so, then the exact clock of the DMG would be 4.194303999987285454853, with 4.194304 being rounded up. Am I on the right track here? It seems like I'll need to find a program that can slow my videos down by extreme amounts of decimals, though... I'm very picky, so I'd rather not round the number up because I want it to be as precise as possible. To my knowledge, there are none whatsoever. You can look up any games that are incompatible with the SGB, but I'm pretty sure there are none that don't work because of the different clock rate. As far as I know, the Game Boy is not "complex" enough to care.
You realize that you're limited by the framerate of the video. You can only be accurate to 1 frame. You can set a custom framerate for the video, but if you post it on youtube or elsewhere on the internet, it'll automatically be converted into something standard like 60fps or 30fps.
Yeah, you're right. Sorry, I wasn't thinking straight when I asked that. Now I feel dumb. >< Still, getting it as accurate as possible would be nice. I'm still not sure if my calculations are correct (I'm horrible at mathematics, so there's that), but I've gone with 95.81% speed, which seems to be good enough. Now, once I know for sure that the speed fix will be fine for both regions, I'll get that done ASAP so that I won't have to re-time the videos in the future.
The Japan-only Super Game Boy 2 runs at the correct clock speed, FWIW. This is ignoring any issues related to PAL.
I know, but I don't have one right now, so until I can afford one, it's easier (and definitely cheaper) to modify my existing one.
With the speed fix you disconnect the clock signal from the SNES and add a 4.194304 MHz crystal to the SGB. This is also how the SGB2 works.
So then you mean the SGB only uses its own clock signal once you modify it, not before (because it doesn't have one before modification)? That makes sense to me. Thanks.
