My suspicion is that there is no direct correlation between the model and the accuracy. It is more likely that each watch will come out slightly different from the production line. You got lucky with a very precise F91W, but it doesn't mean they are all that accurate. My A158 runs one second fast every 4 days or so, while yours runs slow over time. Reading up about quartz watches will shed light on the many different factors that effect accuracy (like the state of the battery and even the temperature). Nice video btw.
Thank you for sharing; that's also a good accuracy, about 8 seconds per month. Yes, many factors, and the quality of the quartz crystal oscillator component also has a big impact on the accuracy. It looks like Casio has a better supply source compared to Skmei, but in detail it's like randomly some are better than the other, and I'm lucky with the F91W.
My DW-5600 is 10 sec fast a month. My DW-6900 and DW-9052 are also 10sec fast. My best Gs are about 3 to 5 secs fast (GD-350, GD-400, GD-100). I find it interesting cause the more inaccurate watches have older modules, that are basically the same as functions are identical, while the better ones all have similar world time modules (and show same firmware number on hidden screen test). Now my best ones are simple Casios. The WS-1500 which is two sec fast, while my AE-1500 is two sec slow. My best of all though is not a digital. My Duro is just one sec fast a month! Thanks for the video. It inspired me to test all my Casios again. With the exception of the GD G-Shocks mentioned, I did the same test almost a year ago. It’ll be interesting to see if after a year there is much variation. It’ll also serve to validate my seat of the pants impressions of my GDs as I didn’t test them last year as I didn’t have them yet.
Thank you for sharing. And about the Duro accuracy, that's very impressive; I never thought it would be that accurate. By the way, this 1-month testing is a bit slow to know if a watch is accurate or not. I'm thinking of other faster ways to get discrepancy data, maybe by screenshot of the stopwatch vs. atomic clock. Will post about it when ready :)
@@SamsWatchReview yes, I was also impressed by the Duro. It was brand spanking new at the time I tested it. FWIW, an Addiesdive Sub was 6 sec fast in that test. And it has the same Miyota movement as the Duro. So either my Duro was a fluke, or Casio regulates it in some way. Something they do as the Duro hit all the marks and the Addies didn’t. All my Casio analogs have hit all the marks, the Addies didn’t.
I think the parameters of electronic parts might differ slightly, and as was already proposed, the battery condition. Thanks for interesting experiment 🙂
I think it is a bit like the silicone lottery. Some chips clock higher than others. Crystals are organic and perform differently. Some have more or less imperfections than others. Most CPUs are cut from the same silicone slab but some will clock higher than others reliably. They just get binned according to how high they can go reliably within a safety margin. I have one F91W that gains 0.5 seconds per day and another that is much more accurate (still testing). I have a Casio calculator watch that keeps more or less perfect time. I suspected they 'bin' the crystal quality accordiing to model / cost so the lowest cost watches would get the least accurate crystals? Still, for £10, it is pretty hard to get annoyed lol. What do we expect of a £10 watch after all? Most high end watches are not that accurate tbf.🤣
Thank you for stopping by and sharing. Yes, it's like a lottery somehow, but anyway, they're still under the accuracy rating from the specification. Except for the copies (Skmei), that's about 1 second per day, although that would still be better than many much more expensive mechanical watches :D
Funny how the most inaccurate are still less than 10 minutes a year. Back before quartz became a thing they would still have been far more accurate than any other wristwatch, no matter what the price.
Interesting findings! Casio have mastered the accuracy 😎 Thanks for sharing 🙏
Thanks for watching. Have a great day :)
My suspicion is that there is no direct correlation between the model and the accuracy. It is more likely that each watch will come out slightly different from the production line. You got lucky with a very precise F91W, but it doesn't mean they are all that accurate.
My A158 runs one second fast every 4 days or so, while yours runs slow over time.
Reading up about quartz watches will shed light on the many different factors that effect accuracy (like the state of the battery and even the temperature).
Nice video btw.
Thank you for sharing; that's also a good accuracy, about 8 seconds per month.
Yes, many factors, and the quality of the quartz crystal oscillator component also has a big impact on the accuracy. It looks like Casio has a better supply source compared to Skmei, but in detail it's like randomly some are better than the other, and I'm lucky with the F91W.
That's why casio f91w is legend 😅
I think it would have been fun to see/hear the differences with hourly chime on 🔔
That's actually a great idea :D
@@SamsWatchReview I look forward to that video Sam!
My DW-5600 is 10 sec fast a month. My DW-6900 and DW-9052 are also 10sec fast. My best Gs are about 3 to 5 secs fast (GD-350, GD-400, GD-100). I find it interesting cause the more inaccurate watches have older modules, that are basically the same as functions are identical, while the better ones all have similar world time modules (and show same firmware number on hidden screen test).
Now my best ones are simple Casios. The WS-1500 which is two sec fast, while my AE-1500 is two sec slow. My best of all though is not a digital. My Duro is just one sec fast a month!
Thanks for the video. It inspired me to test all my Casios again. With the exception of the GD G-Shocks mentioned, I did the same test almost a year ago. It’ll be interesting to see if after a year there is much variation. It’ll also serve to validate my seat of the pants impressions of my GDs as I didn’t test them last year as I didn’t have them yet.
Thank you for sharing. And about the Duro accuracy, that's very impressive; I never thought it would be that accurate.
By the way, this 1-month testing is a bit slow to know if a watch is accurate or not. I'm thinking of other faster ways to get discrepancy data, maybe by screenshot of the stopwatch vs. atomic clock. Will post about it when ready :)
@@SamsWatchReview yes, I was also impressed by the Duro. It was brand spanking new at the time I tested it. FWIW, an Addiesdive Sub was 6 sec fast in that test. And it has the same Miyota movement as the Duro. So either my Duro was a fluke, or Casio regulates it in some way. Something they do as the Duro hit all the marks and the Addies didn’t. All my Casio analogs have hit all the marks, the Addies didn’t.
I think, for the pure test all watches must be loaded with new batteries
Understood, thank you for the suggestion :)
I think the parameters of electronic parts might differ slightly, and as was already proposed, the battery condition.
Thanks for interesting experiment 🙂
That could be one of the reasons. Thanks for watching :)
I think it is a bit like the silicone lottery. Some chips clock higher than others. Crystals are organic and perform differently. Some have more or less imperfections than others. Most CPUs are cut from the same silicone slab but some will clock higher than others reliably. They just get binned according to how high they can go reliably within a safety margin. I have one F91W that gains 0.5 seconds per day and another that is much more accurate (still testing). I have a Casio calculator watch that keeps more or less perfect time. I suspected they 'bin' the crystal quality accordiing to model / cost so the lowest cost watches would get the least accurate crystals? Still, for £10, it is pretty hard to get annoyed lol. What do we expect of a £10 watch after all? Most high end watches are not that accurate tbf.🤣
Thank you for stopping by and sharing. Yes, it's like a lottery somehow, but anyway, they're still under the accuracy rating from the specification. Except for the copies (Skmei), that's about 1 second per day, although that would still be better than many much more expensive mechanical watches :D
good word bro
Thank you :)
❤casio
Funny how the most inaccurate are still less than 10 minutes a year. Back before quartz became a thing they would still have been far more accurate than any other wristwatch, no matter what the price.
Yes, indeed. Even the worst in this group has a difference only about 1 second per day.
F91 made in thailand 😮
Yes, the F91 that I got was made in Thailand.