I want to work with music production - in particular with Sibelius software. I same time I need new laptop and I am wondering - does laptop build-in sound card/chip makes any difference in quality of music production (not only in Sibelius software, but in other DAW software too)?
I know, that for heavy processing I need strong CPU, at least 8GB RAM and a lot of storage for work files, but I am worried about sound card/chip in laptops.
The built-in sound card on a laptop often ranges between very poor quality to decent, but generally they are not high quality for two reasons: DAC and Latency.
Interface Latency
The main issue with laptop sound cards is latency of the interface. For example, a built-in laptop sound card might have a latency of 20-50ms, while an external card made for audio work can have a latency of <10ms or even <5ms.
When an interface has latency, music production might suffer when you are merging different tracks or attempting to match beats DJing etc. <10ms is usually imperceptible, but on high-quality studio soundsystems or PA systems the latency of 20-50ms can start to become noticeable. So, while in your home studio the latency may not be noticeable, once recorded and played on a studio setup you may notice beats and other artifacts to seem slightly off.
DAC
A good digital analog converter is expensive, and for this reason laptops and mobile devices are often lacking in quality of their DACs. External sound cards tend to have their own DAC, and these are generally higher in quality than those that ship with the computer. The DAC is important for you listening to music as you create it. If your DAC is of poor quality, you will get a less-than-true rendering of the audio you're creating through your speakers. This can include distortion, noise, delay, jitter, and various forms of digital filtering. So, you may notice that music you create using a built-in laptop DAC sounds different when recorded and replayed through a high-quality DAC.
Also, the nature of the power supply for the audio interface (in the case of a built in laptop, this shares the system's PSU, which is typically not designed ideal for audio and may generate interference and noise as well) and the shielding of the components will be important considerations as well in the quality of an audio interface.
Conclusion: Get a good sound interface, work from there
That said, the addition of a good external sound interface to a laptop can make audio production and performance much better quality. I will echo @RoryAlsop's statements that just having a good CPU, fast SSD and decent amount of RAM should do the trick otherwise for your purposes. As a first step, getting a good sound interface should make the biggest difference and from there you can fine-tune your needs.
You are correct that there are specific concerns, but what you may not be aware of is what actually impacts high quality sound production. From most to least important, here is my list:
Sound card has no affect on the audio processing of a DAW, or on the music you export from that DAW. It only handles audio output and input....aka what you hear.
Audio processing of DAW is done totally in "software". Meaning your CPU does all the work to run the synths and effects. At the end of it all it takes the final master buffer of audio and exports it to file, or gives it to your sound card to play.
Your sound card takes that audio and processes it any way it wants and converts to analog output. So your sound card CAN change what you the producer hears as you produce. For example my old creative x-fi card has game mode, music mode, and movie mode. Each would do different Eq'ing behind the scenes. Which one was the flattest and natural?? I don't know. Most basic sound card will probably just present the audio flat to you.
If you are planning to record, the internal sound card will not simply suffice. It will not be able to power a condenser mic, in addition, internal sound cards are NOTORIOUS for recording interference.
