44 out of 48 is definitely too high. Keep in mind that the OS needs some RAM to manage the RAM itself.
Assuming no other software using significant RAM is running on that box to any significant degree, I'd suggest capping at no more than 40GB.
SQL DBA,SQL Server MVP(07, 08, 09) Prosecutor James Blackburn, in closing argument in the Fatal Vision murders trial:
If in the future, you should cry a tear, cry one for them [the murder victims]. If in the future, you should say a prayer, say one for them. And if in the future, you should light a candle, light one for them.