18 April 2021, 17:04 | #1 |
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Question: CPU Emulation Speed (?)
Hi guys,
Have a good weekend ... Pls, I would like clear up doubt. In the option "CPU Emulation Speed -> Fastest possible", if I enable this option, the system loads very fast and runs very flow. But, at the bottom of the emulator window, it shows the "CPU 100% & the "FPS 49.8". I wonder if this means that my PC is using 100% of the CPU or it refers to the CPU of the emulated system, the A1200. One of my concerns is that may be using 100% of my PC CPU (Windows 10). Pls see the picture: https://i.imgur.com/aSCYyF8.jpg However, if I change the option "CPU Emulation Speed -> Approximate A500/A1200 or cycle-exact", the CPU was so variable: it went from 0% to 20%, 24% etc. in an instant (playing). Pls see the picture: https://i.imgur.com/kos1TIV.jpg Pls, I would like to know if the "CPU at 100%" only refers to the CPU of the emulated system and not to my PC in general. Many thanks in advance. |
18 April 2021, 20:28 | #2 |
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It means it uses as much as host CPU power as available (=the faster the PC, the faster the emulation). But note that main emulation code can only use single CPU core.
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19 April 2021, 15:58 | #3 |
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Thank you ever so much, Toni Wilen.
It is not clear to me... what are you referring to "host CPU" ? refers to the CPU of the emulated system and not to my PC ? |
19 April 2021, 19:34 | #4 |
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Host CPU is the processor in your PC - Intel or AMD.
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20 April 2021, 02:09 | #5 |
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20 April 2021, 02:18 | #6 |
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Windows task manager shows total CPU usage of all cores, so on a multicore CPU it won't show 100% unless all cores are busy.
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20 April 2021, 02:33 | #7 | |
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Quote:
https://i.imgur.com/aSCYyF8.jpg |
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20 April 2021, 08:51 | #8 | |
son of 68k
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Quote:
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20 April 2021, 10:11 | #9 |
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As already said WinUAE uses 1 core of your Intel/AMD CPU. WinUAE shows usage of that one core. When emulating real speed A1200, that Intel/AMD core is powerful enough to have some idle time so it doesn't show 100%. When emulation is Fastest possible, it uses 100% speed of your Intel/AMD core, so Amiga speed is as fast as possible on your Intel/AMD CPU.
So for example, on some weak Celeron CPU it will take ~25% of one of its cores to emulate 100% fast A1200. When you tick Fastest possible it will use 100% of Celeron core and emulated A1200 will be ~400% fast. On some powerful Ryzen CPU it will take ~10% of one of its cores to emulate 100% fast A1200. When you tick Fastest possible it will use 100% of Ryzen core and emulated A1200 will be ~1000% fast. |
20 April 2021, 10:18 | #10 |
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Your computer obviously has six CPU cores which is why one 100% of one CPU shows as 16% in the Windows Task Manager. As said multiple times, the CPU usage indicator in WinUAE shows the load of one PC CPU core, not of the emulated CPU.
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21 April 2021, 02:52 | #11 |
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I fully understood!
I really appreciate it. Thanks once again meynaf, rutra80 and grond. |
25 April 2021, 05:04 | #12 | |
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Quote:
Please see the attached pictures if this isn't clear enough, taken from the laptop I'm using to type this reply. It has an AMD Ryzen 3500u CPU, with 8 logical processors. |
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