That's...weird and wacky. Have not experienced any problems using Acheron yet here in WoW 3.3.
The last download is using libraries (Ace3) dating from May, though. You running any updated mods that use Ace3? If not, you may need to replace the Ace3 libraries included with it from the latest from here.
Getting the following errors fairly consistently with r77 (USEng client/server, WoW 3.0.9 live, standalone updated libs):
Acheron-1.1.5\\Display.lua:575: attempt to index field '?' (a nil value)\nAcheron_Graph-r5\\Display.lua:211: in function `PopulateGraph'\nAcheron_Graph-r5\\Display.lua:89: in function <Interface\\AddOns\\Acheron_Graph\\Display.lua:87>\n(tail call): ?:\n<in C code>: in function `PopulateEntries'\nAcheron-1.1.5\\Display.lua:339: in function `ShowDeathReports'\nAcheron-1.1.5\\Display.lua:295: in function `func'\nInterface\\FrameXML\\UIDropDownMenu.lua:561: in function `UIDropDownMenuButton_OnClick':\n<string>:\"*:OnClick\":1: in function <[string \"*:OnClick\"]:1>
Acheron-1.1.5\\Display.lua:575: attempt to index field '?' (a nil value)\nAcheron_Graph-r5\\Display.lua:211: in function `PopulateGraph'\nAcheron_Graph-r5\\Display.lua:89: in function <Interface\\AddOns\\Acheron_Graph\\Display.lua:87>\n(tail call): ?:\n<in C code>: in function `PopulateEntries'\nAcheron-1.1.5\\Display.lua:220: in function <Interface\\AddOns\\Acheron\\Display.lua:220>\n(tail call): ?:\n<in C code>: ?\n<string>:\"safecall Dispatcher\":9: in function <[string \"safecall Dispatcher\"]:5>\n(tail call): ?:\nAceGUI-3.0-19 (Ace3):267: in function `Fire'\n...s\\Ace3\\AceGUI-3.0\\widgets\\AceGUIWidget-TreeGroup.lua:91: in function <...s\\Ace3\\AceGUI-3.0\\widgets\\AceGUIWidget-TreeGroup.lua:89>
Happens when I select a line (or the entire death report) and report it to raid or party.
Very disappointed with the removal of the right-click player menu entry. After trying out the LDB option (with StatBlockCore) & the command line, have found those nowhere near as intuitive to use as the right-click. Add it back and retain the two new options?
Also, a problem. First raid since the Sept 5 changes (r81427, standalone libs, 2.4.3 Live, USEng), a Kara badge run. One new offtank died after a trash pull (the only death of that pull). I was within range of the person, but the person was not accessible via the Acheron menu at all. The name did not appear in the drop down list, ever.
Closed the window & reopened, did that a couple more times up to 5 minutes later, he never showed up in the Acheron list. The person was in the raid since the beginning. Same thing with a couple of other deaths throughout the run. A couple showed up, a couple did not (that I was within range of).
To test these kinds of addons you need to do it in a raid.
For 100% behavior-accurate conclusions, sure. For proposed conclusion drawing based on long experience, its not really necessary. The poster was saying this mod was doing something without providing the hard data (numbers, etc.) and/or not running it without other mods being present. My hard data here for this-mod-alone in-combat usage & self-deaths shows 0 CPU usage. Also shows 0 CPU usage in an instance party in-combat.
Its difficult to impossible to test CPU usage in a raid unless you have 9 willing volunteeers who will put up with you lagging and holding things up when CPU profiling is turned on and you are staring at the OptionHouse/FuBar_Usage/Profiler/etc. tables. Raid lag can be caused by many different things. Its a reasonable assumption to make that mods which use excessive CPU time when OOC & idle or in combat solo or in a party will amplify and/or continue this behavior when in a raid.
Based on that, the probability of Acheron eating tons of CPU during trash mobs is slim and its much more likely some other mod is causing it for that person. Again, not a 100% behavior-accurate conclusion, but good enough ;).
I did "extensive" CPU testing on Acheron with standalone libs here. Extensive meaning killing helpless baby spiders on my level 11 test character, solo. As well as letting them eat me (er, so to speak).
At no time did Acheron ever use excessive CPU time; it used none/virtually none at all times, including when dying. And neither did the libs it used, above the steady no-mod CPU state they normally did. That person's lag issues most likely due to another mod.