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Image1, which camera have you got ?
Some cameras offer lossless compression of raw files, which works out faster than using uncompressed raw files because the extra time taken to do the compression is much less than the time saved by having to write less data to the memory card.
Any WB change to any image can push data (pixels) to the extremes of one or more colour channels. The less accurate the WB was at capture time the more significant some of those changes may be. Once pushed to near the extremes there is less tonal separation and some information may be lost. e.g. a bright red flower may take on the appearance of red blob with little or no texture in the petals.
A well exposed jpg of a not too contrasty scene with nearly correct WB can look very good, but muck those up and try to correct them and you could end up with information loss. Any 10-16-bit-per-channel format (not jpg) including raw may retain more of that info but eventually even they will be damaged if the errors were too great to begin with.
Using the tungsten setting for near-tungsten lighting is recommended by Canon, for example, in favour of auto WB. Auto WB works best at or near daylight and becomes less accurate at the higher and lower colour temperatures such as tungsten. Beware that if you shoot daylight scenes with the tungsten setting then everything will look very blue, so Auto WB may be the safest option.