Add an Overclock Option to Avoid Slowdowns

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mambrino
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Add an Overclock Option to Avoid Slowdowns

Unread post by mambrino »

Hi,

Would it be possible to overclock the core to avoid slowdowns in games like megaman, double dragon, gradius, blaster master, ...?
It would greatly improve the playability of these and other games.
ToothbrushThreepwood
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Re: Add an Overclock Option to Avoid Slowdowns

Unread post by ToothbrushThreepwood »

Have you tried turning on the ‘Extra Sprites’ option in the Audio & Video-options from the OSD core menu?
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mambrino
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Re: Add an Overclock Option to Avoid Slowdowns

Unread post by mambrino »

yes, I always have it on, I understand that it eliminates the flickering of the sprites when the limit is reached (8 sprites per scanline), I think it doesn't affect the speed of the cpu / ppu at all, and if it does, with this option active I still notice slowdowns in many games.
FPGA64
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Re: Add an Overclock Option to Avoid Slowdowns

Unread post by FPGA64 »

The FPGA is accurate. if the game slows down thats what happens on real Hardware. You cant just overclock one part of the system without it having a ripple in the other parts. FPGA run all the chips simultaneously, having one ruuning too fast will break the system.
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mambrino
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Re: Add an Overclock Option to Avoid Slowdowns

Unread post by mambrino »

I understand it, but other cores like gba, megadrive, snes, and some arcades implement this functionality. It's true that some games don't work properly, but many others work without problem. I don't know if in these cases only the cpu or the rest of the system is overclocked, but for practical purposes it's functional and an improvement when playing these games. Also, it can be enabled or disabled from the menu, so it wouldn't affect compatibility.

imho, having a core that behaves exactly like the original machine is very interesting, but also having the possibility of going further and being able to overcome its limitations in favor of an improvement in the gameplay can be very useful too.
N.Master
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Re: Add an Overclock Option to Avoid Slowdowns

Unread post by N.Master »

Hi,
I am not expert in NES, but it seems that NES have all it's timing related to the main CPU.
That is the reason why NTSC and PAL NES have different working frequencies.
With an Overclocked CPU, video timings will no longer be accurate, and sound will be faster and higher pitched.
More modern systems have separated clock signals for sub systems, but the NES is very minimalistic
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darksakul
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Re: Add an Overclock Option to Avoid Slowdowns

Unread post by darksakul »

Sometimes the slowdown is often bad coding in the game and not the hardware or emulation of the hardware.

Metal Slug on the Neo Geo as been found running on full speed with a rom hack
For the SNES (on original hardware it would be a hardware mod) look for the SA-1 Hacks various games. Hacking the game to support the SA-1 chip speeds up those games that have the hack drastically.

Problem with forcing a overclock often breaks the game
It is my great regret that we live in an age that is proud of machines that think and suspicious of people who try to.
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mambrino
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Re: Add an Overclock Option to Avoid Slowdowns

Unread post by mambrino »

N.Master wrote: Wed Oct 13, 2021 11:51 am Hi,
I am not expert in NES, but it seems that NES have all it's timing related to the main CPU.
That is the reason why NTSC and PAL NES have different working frequencies.
With an Overclocked CPU, video timings will no longer be accurate, and sound will be faster and higher pitched.
More modern systems have separated clock signals for sub systems, but the NES is very minimalistic
ppu runs at 3 times the cpu clock speed, and also shares the clock signal with the cpu, so yes, I hadn't thought about it but this could be a problem for overclocking. If that were not enough, the cpu also generates the sound, so as you say, increasing cpu speed, it will be faster and higher pitched.
I have proposed it in case someone comes up with an idea to do it, but I suppose that are inherent to the machine.
Larkhainan
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Re: Add an Overclock Option to Avoid Slowdowns

Unread post by Larkhainan »

It's a shame the good explanation for why this doesn't seem like a good option got buried in having a normal one :/
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Re: Add an Overclock Option to Avoid Slowdowns

Unread post by Xbytez »

I have cleaned up and removed a number of posts in this thread, discussion is fine, however personal attacks towards other forum members is unacceptable behaviour and will not be tolerated here at all.
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