China saves more than many other developing nations, it is at the top of the chart in terms of savings rate. About half of the nation's income is saved and invested (how it is invested is another matter). It is not that Malaysia is doing bad, they are a normal case but they don't save enough to grow at high rates sustainably without significant external capital. Rapid expansion of the economy during the capital intensive phase requires as the name suggests, intensive capital. At this stage the nation cannot just exploit labour intensive and non-capital intensive industries based on their advantage in low labour costs. Capital can either come from elsewhere or from domestic savings. Most of China's capital comes from domestic savings. China's external debt is 15% of GDP which is low compared to other nations such as Malaysia's 75% and foreign reserve is higher than foreign debt.
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https://data.worldbank.org/indicator/NY.GNS.ICTR.ZS?locations=CN-MY&view=chart&year_high_desc=true
This results in low external debt for China even though its total debt is increasing, it is internally financed and China also controls its own monetary policy. Giving China the ability to undertake massive projects. It buffers China from many of the shocks of the international credit supply and monetary policy (US Federal reserve policies has a major impact upon the global economy, directly and indirectly), but global economy and policies still affect China, just not as severely as compared to other nations and is less direct.
China chose the more difficult but more secure way to finance its growth. Instead of living the high life and finding external creditors to finance its growth, the nation saves half its income mainly in state banks. China can't just print money without consequence. The large amount of aggregate savings creates a relative abundance of domestic credit supply meaning relatively cheap money (compared to domestic low savings senario). For many developing nations, interest rates would be too high to borrow from if they just depended on domestic savings as the credit supply (due to low savings), thus these nations look for outside creditors to lower interest rates for there to be an environment conducive to business growth.
For many developing nations, a large part of their debt is foreign, from nations that have large savings. The positive aspect is that they are able to develop many essential and profit generating projects with ease. The negative aspect is the instability that might occur due to the economic structure of their own economy. For example a resource focused economy would be hit hard (or benefit immensely but is unstable causing long term problems) due to cycles of the commodity market or geopolitical events that impact energy sector heavily, resulting in a major devaluation of their currency such as in the case of Brazil and Russia in recent years. This currency devaluation combined with large foreign debt creates a situation where they are compelled to deleverage.
Many developing economies experienced this throughout various global business cycle downturns. Their currency is devalued relative to USD but must pay back debt denominated in USD, meaning a larger percentage of their nation's GDP must be used to pay debt, creating deleveraging. This constricts the money supply causing projects to pause, these projects might be essential in generating future value, slowing the economy down due to lower current spending and long term issues from unfunded projects. Saudi Arabia mitigates this somewhat through a peg with the USD, large reserves, and a strategic relationship with the US.
Stability of money supply is essential for any economy, doesn't matter too much where it comes from, as long as it is stable then there would be a good environment for growth.