Yes, jim has to save vs. each effect, and if they happen to hit him again, the effects will stack.
Originally Posted by Amnistar
Ongoing damage effects never
stack unless explicitly stated that they do (and I don't know of any such effect.)
I'm pretty sure that identical effects from identical sources do not "multiply", that is, they only require one saving throw - I would count identical monsters as identical sources for this purpose. So if you were slowed by an Aboleth Slime Mage's Slime Orb and also by an Ice Archon Rimehammer's Maul, you would have to save against each effect separately. But if you are slowed by the bites of two Clay Scouts, you only need to save once.
That's how I would rule, but that is not RAW
. The general rule is:
"Save Ends: The effect ends when the target makes a successful saving throw against it."
"Overlapping Durations: If a target is affected by multiple powers that have the same effect but end at different times, the effect with the most time remaining applies."
Implying that if it's the same effect from different sources, you still only need to save once.
As for (save ends both) I found a better written rules text - see page 279 under Saving throws:
"Another kind of effect is like an imp’s hellish poison, which includes both ongoing poison damage and a –2 penalty to Will defense. You
don’t make separate saving throws against the ongoing poison damage and the Will defense penalty; you make a single saving throw each round against the hellish poison itself.
Some powers create effects that require multiple saving throws to fully escape. These powers include aftereffects that apply after you save against the initial effect. For example, a power might knock you unconscious until you save but have an aftereffect that slows
you. Once you save against the unconscious condition, you need to save against the slowed condition before you’ve fully escaped the power’s effects. An aftereffect doesn’t begin until after you’ve rolled all your saving throws at the end of your turn."