VP Sequence Preview Jerky on powerful MAC; smooth on vanilla PC... why?

[John Goodyear]

I have had a rather plain vanilla all-in-one PC (3-year-old HP Inspiron with 4 processors & Intel graphics processor - Geekbench 5 CPU single score of 1021, CPU multi score of 3746, Compute score of 5758, 12 GB RAM) and have just gotten a much more powerful iMAC Pro (10 intel W processors w/ Radeon Vega Pro 64X graphic processor and SSD, 32 GB RAM, Geekbench 5 CPU single score of 1126, CPU multiscore of 9488, Compute score of 62856).

I have VideoPad version 8.45 for the PC and version 8.66 for the iMac Pro.

For the SAME stored VP project, the sequence preview on the PC (after appropriate waiting so that the CPU settles down after completing preview processing), is smooth...  I can easily synch singer mouth movement with a separate audio track.

On the MAC for the same VP project, the sequence preview is jerky... maybe 1 to 2 frames per second, confounding the synching of lips in the video with music on the audio.

Investigating this, I found that for the same VP project, the PC exports an .mp4 video file that is only 1/8 the size of the MAC mp4 file... with same resolution and frame rate, both at "default quality and resolution" settings and same H264 encoder.

Why???

More observations on my problem above...

I read that when VP removed the option of selecting preview resolution, it instead chooses something based on the resolution of the monitor being used.  My PC monitor is 1920 x 1024; my MAC monitor is 5120 x 2880 pixels, a total of 7-1/2 times as many pixels.

Could it be that the 2-1/2 speedup on CPU processing of my MAC is being overwhelmed by the 7-1/2 times more pixels?

How do I get around this?  Is there a way to reduce display resolution that VP sees?

Also, perhaps the greater resolution of the MAC causes VP to treat my 1,920 x 1,024 video as is, no resampling, while the lesser powerful PC with fewer display pixels triggers some kind of down sampling in VP, hence leading both to better preview behavior and smaller exported file sizes. 

How can I set or control this possible resampling or lack of resampling?

Finally, I notice my MAC has a slightly higher rev number of VP than my PC (8.66 vs 8.45). 

Where do I find old versions of VP so I can go to an older version (maybe even one of the versions so old that I can control sequence preview resolution and frame rate... how long ago or what rev number were those still user-adjustable?)

Thanks!

[macfly]

Hi John. You're correct that the 5K retina display of the Mac causes the "jerky" preview. Please try resizing the size of VideoPad's window to a smaller one then clear the cache in Preferences -> Disk then reload the project. For the export file size, please try selecting HD preset or 1080p resolution, video quality to High and Lossless Export to Off.