Low frequency noise is different from high frequency noise. High frequency noise is a very sharp sound with a very short wavelength. It can decay rapidly with the distance getting farther or encountering obstacles. For example, the point sound source of high frequency noise can drop by 6 decibels every 10 meters.The low-frequency noise is not high in decibels, but it decreases slowly with a long wavelength, so it can reach the human ear from a long distance. For example, the current sound of transformers and the sound of large refrigerator are low-frequency noise. For example, high-frequency noise is like ants, and low-frequency noise is like elephants.
The X2240 upgrade to the X4 640 is not meaningful unless it is opened more. It is just two more cores, and the X4 640 is now more expensive. Hard disk upgrades have little impact on performance. Suggestion: 1. Go to Taobao and buy two 1G ddr2 667 memory modules, about 45 of which are plugged in., 2. Play online games and upgrade the graphics card to HD6770.About less than 600 yuan. 3. It is not a problem that the power supply is noisy. Just disassemble it to remove the ash and add some lubricating oil.
Lenovo G460ALN 14 inch laptop (i3-380M 2G 500G 512M single display wireless camera DVD recording) Magic Black 3499 Lenovo G470GH-ITH 14.0 inch laptop (i3-2310M 2G 500G camera DVD burning Win7) Dark brown 3699
