Sinclair ZX80 / ZX81 / Z88 Forums

Hi,

I have read of the 'noWAIT' mod on the ZX81. Does anyone have any more details on this and how it is implemented? I cant find any specifics on it?

Also, is there any recommended benchmarking and test software for the ZX81? speed tests, timing tests etc?

New to the ZX81 world, coming from the ZX Spectrum world.

Many thanks in advance.
Andy

For the wait mod, see this topic

Mark

Thanks Mark,

Being a newbie (or maybe idiot), this is not the whyWAIT(?) mod, this is the noWAIT mod? Is there any benchmarking tools that can be used to see if it is working or the impact?

Thanks so much.

Andy

Andy, you are not an idiot you only learn by asking and the good folk here have come to my rescue on many occasions and very grateful am I for their forbearance!

From what I remember it's supposed to be a 10% speed increase. A zeddy in slow mode runs at about 0.80 MHz give or take the accuracy of any individual resonator and 10% amounts to a speed of about 0.88 MHz which in my view is not worth bothering with and in real world use I found it added nothing measurable or useful speed wise. For a decent speed increase, the "BigBang X2" ROM is the way to go.

A link to relevant thread...

https://www.sinclairzxworld.com/viewtop ... g+bang+rom


Benchmark program.

No wait and why wait are the same.
Really not worth bothering.
Some programs rely on original timings and get confused when the Zeddy is modified this way.
The big bang rom does work fine.

great. thanks for the help. I saw on thread that whywait improved performance by 10% and noWait by 30% which was a little confusing! THanks again.

Any recommended software for measuring / benchmarkins ZX81 speeds?

Andy

I included a simple benchmark program in my post just download and run, anything else is meaningless as benchmarks only test a certain set of variables and not the software you may use in real life so the clock speed program is all that's really needed I would have thought.

andys wrote: ↑Wed Nov 27, 2024 7:32 pm I saw on thread that whywait improved performance by 10% and noWait by 30% which was a little confusing!

Do you mean this topic?
That (around) 30% only applies to a TS1000 or USA ZX81 when running in SLOW mode at 50Hz video mode instead of running with a 60Hz video mode.

This is irrelevant for a European ZX81 because it already has 50Hz video by default.

Mark

Paul wrote: ↑Wed Nov 27, 2024 4:43 pm Some programs rely on original timings and get confused when the Zeddy is modified this way.
The big bang rom does work fine.

Hi Paul,
Are you able to tell, which programs are confused when using whywait modification?

Sorry, I don't know about such a List.
Generally everything that relies on exact timing in slow mode might be affected.
Gameplay, hires, driver for hardware.
Although exact Timings are better done in FAST mode many programs were also written on "everything is possible" thursdays