PedroPM94, have you tried older 0.582 version of Demul as well?
In my case there are games that not working in latest build, but working good in that one.
also, only in case if you are eager to find a working dreamcast emulator and, for example, if you experience slow loading times [slower then before] in native Windows UE4 games:
[as was I some years ago with another emulator for N64 - Mupen64]
0. Go to laptop bios and check:
1. Intel Virtualization Technology [ON]
2. Intel AES-NI [ON]
3. VT-d [ON]
4. Graphics Configuration -> DVMT Pre-Allocated [lowest possible]
1. Reboot & now go to active power plan:
0- Intel(R) Graphics Settings [Balanced]
1- PCI Express - Moderate power savings [off is the same. If you care about noice and long life of your laptop - leave it to Moderate. Same is for step before.]
2- Processor power management [Active, 0-95] [after making all the steps and testing - try to revert it back to 0-100 because it's faster by default - when your cooling system is in very good & clean condition]
2. Now to Inel HD Control Panel:
3D:
1- MSAA [use application settings]
2- Conservative Morphological AA [off]
3- Balanced
Power:
1- Balanced
2- Automatic Display Brightness [off]
3- Display power saving technology [off]
3. And change Nvidia settings to balanced [and after making all the steps and testing try to revert it back to your desired settings too. For more advanced settings google for Nvidia Profile Inspector]
And finally if your results are still the same - it's 99,9% because of Windows Services [maybe broken, buggy], or because of apps in background. [look carefully in Task Manager].
You can check it by installing another clean Windows 10 with disabled updates alongside with existing Windows 10 to keep all your data. Or by installing Windows 7 if you are lucky to have MBR instead of GPT [in another way you will need to convert it].
This final step will be much faster & easier if you will have another small & cheap laptop HDD [if you can unbox external HDD - there is a great chance it will fit in laptop too]