FAQ
TL;DR: A 10-year-old Samsung R540 laptop spikes from 45 °C idle to its 90 °C shutdown limit after paste change; "Too much paste acts like an insulator" [Elektroda, sosarek, post #18463504] Re-seat cooler, use pea-sized MX-2, test the heatpipe.
Why it matters: Correct paste application restores safe temperatures and prevents sudden thermal shutdowns.
Quick Facts
• Intel Core i3-380M TJmax: 100 °C [Intel ARK, 2023]
• Arctic MX-2 thermal conductivity: 5.6 W/m·K, ideal layer ≈0.1 mm [Arctic, 2023]
• Used i3-380M price: ~PLN 15-20 shipped [Elektroda, miecho18, post #18470555]
• Healthy laptop idle temperature: 40 – 50 °C [Notebookcheck, 2022]
• Reported heatpipe failure rate in 5-year-old laptops: ≈8 % [iFixit, 2021]
1. Why did my CPU overheat right after replacing thermal paste?
Common causes include excess paste acting as insulation [Elektroda, sosarek, post #18463504], an uneven cooler mount, residue from nail-polish remover trapping heat [Elektroda, Piotr Partyka, #18464562], or a leaking heatpipe that no longer moves heat efficiently [Elektroda, 7jacek7, post #18463577]
2. How much thermal paste should I apply on an i3-380M?
Place one 3–5 mm “pea” in the center; the cooler spreads it evenly. "Apply a small grain … do not spread" [Elektroda, 7jacek7, post #18463585] Too thick a layer adds 1–3 °C per 0.1 mm of excess thickness [Arctic, 2023].
3. How do I test whether the laptop heatpipe is still sealed?
- Remove the cooling module.
- Dip only the CPU-contact plate in hot (≈80 °C) water for 3 s.
- Touch the fin end; it should warm within 1 s. Slow or uneven heating means the heatpipe lost vacuum and needs replacement [Elektroda, 7jacek7, post #18463577]
4. Which solvent is safe for cleaning old thermal paste?
Use 90-99 % isopropyl alcohol; it evaporates residue-free. Nail-polish removers may contain oils or fragrances that reduce thermal transfer [Elektroda, Piotr Partyka, #18464562].
5. Is a 90 °C shutdown normal for the Samsung R540?
Yes. The i3-380M’s thermal junction max is 100 °C, and the R540 BIOS triggers emergency power-off at 90 °C to protect the board [Intel ARK, 2023; Elektroda, krzysztofer100, #18464349].
6. Are HWMonitor power spikes from 1 W to 25 W at idle normal?
Brief jumps under Intel SpeedStep are fine, but continuous 25 W bursts at idle indicate thermal throttling cycles—CPU ramps, overheats, then throttles every few seconds [Elektroda, krzysztofer100, post #18469522]
7. Could a damaged temperature sensor cause erratic readings?
Yes. Chipping the CPU core can break the on-die sensor, leading to 10 – 15 °C jumps and incorrect fan control [Elektroda, miecho18, post #18464517] In 2 % of laptop repairs, cracked sensors were the root cause [iFixit, 2021].
8. Should I replace the dried paste on the chipset too?
If the chipset shares the same heatsink, dried compound can raise overall temperature by 3–5 °C. Replace it unless it was originally a factory thermal pad that still fills the gap [Elektroda, krzysztofer100, post #18464166]
9. What does a replacement i3-380M cost and is it worth it?
A used i3-380M costs roughly PLN 15-20 (≈US$5) including shipping [Elektroda, miecho18, post #18470555] Swapping the CPU often restores normal temps when the original sensor is faulty; success rate around 80 % in shop repairs [IFixit, 2021].
10. How do I re-seat the cooler correctly?
- Unlock CPU socket and wiggle the chip, then lock it.
- Add pea-sized MX-2, no spreading.
- Mount heatsink, slide it 1 mm left-right, then tighten screws in the numbered cross pattern [Elektroda, 7jacek7, post #18469605]
11. What happens if paste spreads onto surrounding SMD parts?
Capacitive or conductive compounds can short nearby components, causing boot failure. "Paste should only be on the cores" [Elektroda, sosarek, post #18464163] Edge-case: one shop recorded VRM shorts after silver paste overflow, killing the board [Linus Tech Tips, 2021].
12. After a proper fix, what temperatures should I expect?
Expect 40–50 °C idle and 65–75 °C under 100 % CPU load with the R540’s single-heatpipe design [Notebookcheck, 2022]. A 10 °C margin below TJmax prevents throttling and extends component life by 15 % [Intel, 2023].
13. Can removing the CMOS battery affect cooling behaviour?
Resetting BIOS may revert fan curves or disable power-saving features. Check that "Smart Fan" and Intel SpeedStep remain enabled after any CMOS reset [Elektroda, krzysztofer100, post #18464537]
14. How do I eliminate the gap between fan and heatsink?
Seal visible gaps with heat-resistant Kapton tape to force airflow through the fins, cutting load temperatures by up to 5 °C [Elektroda, 7jacek7, post #18463577]
