Questions on Performance Options

[bob_sun]

Hi,

I would like to ask some questions on PDF-XChange performance setting.

Please refer to the attached screenshot:

PDF_Xchange_Performance.rar

System memory in percentage points:

1. If there are separate instances of PDF-XChange viewer, then does the percentage here refer to each individual process, or to all application instances in total? If it refers to the later, then a mechanism is required for different instances of PDF-XChange Viewer.exe to communicate (inter-process communication), which is not a trivial task in terms of implementation. After all, what does the percentage figure refer to, individual process or aggregation of all instances?

Update: I tested it and found that the limit works only for each individual instance. For example, for a 3G RAM, 10% = 300MB. 10% settings allows several instances each with around 300MB maximum memory usage, in total 900MB.

The new question is that can this be made smaller? Say, not 10%, but 1% or 2%? Or like question 2 below, in absolute size?

2. Is there a way to specify absolute number of memory space in MegaBytes? Different machines have different memory size: 30% means 153.6MB for 512MB ram, 900MB for 3G ram; in addition, the increment (10%→25%→50%→75%) will also be reflected as different memory size on different machines. I guess that the PDF-XChange viewer’s developer might thought this is more intuitive for users, but at least for my case I wish to have control in terms of absolute memory size here, not relative percentage. Can this be done?

Threads usage:
1. Does choosing a smaller number mean less memory usage?
2. What does “synchronous mode” mean?

Bob

[Stefan - PDF-XChange]

Hello Bob_sun,

Please make sure you have the latest build of our Viewer, and you will see both the percentage and the absolute (MB) options.
Also besides the values in the dropdown fields - you can click inside and type in any value you like (e.g. 1% or 37MB)

Need to ask for the number of threads and it's relation to memory, but synchronous mode will try to perform all operations synchronously -so if you want to e.g. scroll a page - you will need to wait for the Viewer to render the new section first before it scrolls down thus reducing the "white pages" you see - but could also decrease the overall performance of the Viewer, or make it feel "slower" on the same hardware. If you do have a good and modern machine - and it's not a shared server - you could give synchronous mode a try.

Best,
Stefan

[bob_sun]

Hello Bob_sun,

Need to ask for the number of threads and it's relation to memory, but synchronous mode will try to perform all operations synchronously -so if you want to e.g. scroll a page - you will need to wait for the Viewer to render the new section first before it scrolls down thus reducing the "white pages" you see - but could also decrease the overall performance of the Viewer, or make it feel "slower" on the same hardware. If you do have a good and modern machine - and it's not a shared server - you could give synchronous mode a try.

Best,
Stefan

Do you mean actually multi-threading will work simultaneously utilizing available CPU multi-core resources? Then if the system is powerful enough (my machine has 4G physical mem and Core Duo 2 processor), then "synchronous mode" would actually enhance performance in that it reduces the delay of "white pages"?

Regarding "make it feel slower", do you mean that basically this will request CPU resources more aggressively hence would compete with other applications: not slowing down itself, but slowing down other applications?


Bob

[Stefan - PDF-XChange]

Hello Bob,

the "slower" comment was for our application only - and it's the same as in the tooltip for synchronous mode - it is used for page rendering, and means that from the time you "scroll" to a new location in your document, until the Viewer actually performs this scroll there might be a slight delay - as the Viewer will first render the new section/page, and only then show it to you - so yes - no white areas, and maybe a slower responding Viewer. This will have no effect on other applications.

Multi-threading is always a good thing - and is recommended to be left on Automatic - the Viewer will then utilize as much of the resources your machine has available as needed.

Best,
Stefan

[bob_sun]

Stefan,

I see it, thanks very much for explanation.

Bob

[Stefan - PDF-XChange]

Pleasure to help BoB

Best,
Stefan