South Korea's semiconductor exports just tripled year-over-year. Is it too much of a good thing?

South Korea's semiconductor exports have been an absolute boon for Asia's fourth-largest economy, sending overall numbers to a record. But the frenetic pace itself is causing concern about what's next.

Semiconductor exports surged 209% from a year earlier to a record $46.65 billion in August, accounting for 47.5% of the country's $98.25 billion in goods exports that month, the Ministry of Trade, Industry and Resources reported earlier this week.

That was mainly due to AI infrastructure demand as large cloud providers including Google and Amazon expanded capital spending, it said.

"In my estimate, semiconductor exports accounted for nearly 80% of export growth in August," Jeff Ng, head of Asia macro strategy at Sumitomo Mitsui Banking Corporation, told CNBC. "Overall export growth was driven by chips, computers, and higher petroleum product prices."

Growth in such figures is generally seen as a positive. But the extremely rapid pace here also raises concern about what happens if, or when, the boom starts to dissipate.

"A gradual slowdown would be manageable. An abrupt stall is a different matter, because the economy already runs at two speeds, and the sectors that would need to take up the slack are the ones under pressure today," according to Dave Chia, an economist at Moody's Analytics.

Monetary policy could also limit the cushion if the cycle turns soon. The Bank of Korea raised its base rate to 3% in August, its second consecutive hike, as core inflation remained elevated.

Chia warned that if chip demand cools while policy is still tightening, "the windfall fades when domestic demand isn't strong enough to take over."