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View Full Version : Effects of Hidden Charts on Resources



Cyberdude
05-11-2005, 04:24 PM
Suppose I have a worksheet with two charts embedded on it. The charts are large enough that when I'm looking at one chart, the other chart is offscreen to the right, i.e., I can't see it. I've often wondered to what extent "hidden" items (charts, text lines, or whatever) consume computer resources? Are they using CPU cycles?
Are they using stuff on the video card? In general, are the hidden items slowing down (and heating up) the computer?
If I have a worksheet full of old stuff, but I seldom ever look at it, is it using resources (other than maybe RAM)? Would I be better off deleting that worksheet, even if I think that some day I just might want to look at it? :dunno

Killian
05-13-2005, 04:25 AM
When you open the workbook, it's entire content (irrespective of whether it's displayed or not) is written to system memory (RAM or Virtual). The number of CPU cycles is relative to the amount of data that has to be processed from the HD to memory by Excel. Therefore redundant charts (or anything for that matter) will have an effect.
If your redendant stuff involves more processing by Excel (updating formulae etc) then this will also add to the overhead for that file (both in terms of work for the CPU and any additional memory requirement) but once a file is loaded, interms of CPU cycles, that's pretty much it.
The video card only gets involved when rendering to the screen (your system/video configuration & drivers will determine how the processing and memory is shared between the CPU, GPU, system and video RAM) so an off-screen object isn't affecting the overhead in that respect.

For the best performance, you should try to keep your current project as lean as possible by deleting stuff you don't need and archiving content you use rarely but want to keep just in case.

Cyberdude
05-13-2005, 08:25 AM
Thanx for the reply, K. I guess what you said makes sense. You didn't emphasize this point, but it occurred to me that no matter where a formula is, it will be executed whenever the sheet it's on is recalculated. I would expect that all sheets are recalculated at the same time, but I'm not sure whether that's true or not. If true, then formulas on all offscreen sheets WILL add to the number of CPU cycles used. A logical extension of this guess is that this would include the Series formulas for charts, even if they are not actually drawn. True??

Killian
05-13-2005, 09:44 AM
True indeed, the calculate method executes either on a specified range, a specifed sheet or at application level (all open workbooks) so in the last case, there is potential for a few CPU cycles! All apply to the respective objects whether they are in view or not