MVS Sarma
Definitely the LM317 is more power hungry. Have a good sized heat sink on it. It has to adsorb 5 volts at maybe 150-200 milliV But a linear is quiet and I thought that the having the receive quiet was worth it. Not measured however. The computer power supply is linear I am pretty sure.
I was not sure whether to change the settings the bias so I left it alone. The uBITX puts out more than 20w on 40 and higher on 80 which I hardly ever use. It is a v3 radio.
It also has large computer heat sinks At least 4x heavier than the stock heat sinks. a 80mm low speed fan and a printed shroud. The output transistors don't go above ambient in digital mode at 20 watts with 1:1 SWR.
My technique is to touch the transistors. I figure the less heat the less degradation there will be.
_Dave_ AD0B