Question: I am trying substitute text in a file with a value in a variable using `sed`:

```
file=1601001000100000003_0003_0_E_2011-11-21_16-52-16.db

sed -i "s/yyyy/$file" tempsbchg.sh

```

but `sed` returns:

```
sed: -e expression #1, char 58: unterminated `s' command

```

I have also tried:

```
sed -i "s/yyyy/${file}" tempsbchg.sh

```

Answer: 
You're right with your reasoning in your 4th paragraph - a high capacity PSU under low load will not need to cool itself anywhere near as much as a lower capacity drive running (struggling!) at high load :)
Side note 1: I don't think you can use specs as guideline at all: noise level not published (and probably - even measured), PFC *can* (indirectly) help, but it's **not hard rule** - bad (loud) fan will be bad anyway

Side note 2: if PSU noise **is fan-noise** (not only they can buzz in the general case), you can think about replacing fans, and select replacement based on noise-level (there are some silent fans from different vendors)

User-reviews *can be starting point* in some degree, but mostly it will your homework - find, poweron in shop, listen, make choice. And I see

> 
> Ultra-quiet 120mm fan delivers excellent airflow at an exceptionally
>  low noise level by varying fan speed in response to temperature
> 
> 
> 

in PSU description, that makes me think or about the case of warranty or about working near the top-limit for PSU (460GTX eats more than 430W in max mode, AFAIK 550W PSU outlined in specs)

> 
> does it help to buy a PSU that has a larger output capacity?
> 
> 
> 

Yes, it *can*, PSU with additional power from good vendor will produce less noise under your everyday load