Question Choppy PDF scrolling: Where is the Bottleneck?

[prateekprakash]

Greetings.

I am a research scholar pursuing PhD, which requires me to view Book PDFs and Technical Research Articles all day long. I used to use Foxit PDF reader free edition earlier, but scrolling was a nightmare because it was very choppy. Sensing that it was due t weak hardware of my laptop, I switched from using my personal laptop to a Desktop PC with Ryzen 4350G, 32GB RAM, SSD, and a $K monitor LG UK650 connected to iGPU via DisplayPort. I would notice CPU spikes during choppy scrolling, so I tried Adobe Acrobat Reader DC Pro. Some files turned smoother during scrolling, as I could see GPU spike upto 50-70%, so I guess Adobe could be using GPU rendering.

Some of my doubts are: Where is the bottleneck occurring?

Is book PDF scrolling as resource heavy as an actual 3D video game?
Would I benefit from a dGPU such as GTX 1650?
Is it the higher resolution screen which stresses the system during choppy scrolling?
Is it 60hz refresh rate causing the choppiness? Would I benefit from 144hz or higher refresh rate?

At the end, all I want is a smooth, choppy-free scrolling experience on the pdf files, just like, say, webpage scrolling on chrome. Any insights would be appreciated.

 

[nosurprises]

Have you try opening the PDF in Chrome and see how that scrolls?

 

[prateekprakash]

Have you try opening the PDF in Chrome and see how that scrolls?

Sorry for the late reply.

Yes, I just tried opening the PDF in chrome. While scrolling is smoother than Foxit PDF, but it is much more choppier than Adobe PDF. Moreover, the CPU spikes to 20-30% in chrome during scrolling, whereas it is 10-15% CPU for Foxit, and 4-6% CPU for Adobe.

I recently got a second 4k monitor Lenovo S28u, and now both the 4k monitors are connected to the iGPU (one via DP 1.2, other via HDMI 2.0). I tried iTunes movies playback fullscreen on 1 screen. The playback is not smooth. Moreover, the CPU is ~15% while the GPU is 95%+ during movie playback.

Is it due to single 1x32GB 2666mHz CL18 stick that I'm using that's causing this issue? would I benefit from 2x32GB 3600 CL18 sticks? I have them ordered, and will report back on my findings.

 

[prateekprakash]

UPDATE:

Installed 2x32GB 3600 CL18 sticks, now my scrolling usages are as follows:

Adobe PDF: CPU=8%, GPU=~30%

Foxit PDF: CPU=18%, GPU: 10%

Chrome PDF: CPU: 22%, GPU:10%

Level of choppiness: Adobe<Chrome<Foxit

Moreover, iTunes movie playback usage on 1 4k screen is: CPU=25-30%, GPU=35-40% and the playback is smooth!

I guess, the single channel slow RAM was posing as the bottleneck.
Now I am happy with the present level of smoothness provided by Adobe PDF, though I would love to try high refresh rate monitors some day!