Sam Garfield, THANK YOU for showing us that link and that there's internal progress on this! Can only hope it's addressed in the next update. (Also, I can't believe I've been living with this for a year now...)

Good news, everyone! Check this out: https://www.reddit.com/r/editors/comments/9koon1/my_bittersweet_love_letter_to_adobe/e73wpel/

To cut to the chase, here was the response from someone at Adobe:

"Great! We got some actual traction on this issue today, mainly due to your fine post. We now have an internal bug filed and hope to have some test cases shortly. Resolving issues like this do take time, but we are now on a path to assisting you and other users with this setup."

To the Anonymous guy with 2 computers, I've found the only work around is putting in a different GPU for the time being. Not ideal but the playback with the gtx 1080 is unworkable

I came here, because we are facing the same problems with two of our computers.
I read through all the comments here and was hoping to find a solution at the end of this thread, but...nothing!? Oh no...

@Alexander Mejia
have you tried changing Project Settings > General > Renderer > Mercury Playback Engine Software Only

Just ran into an issue where i444 h.264 encoded files at 1920x1080 60P play back only at 30fps in the timeline on a Threadripper PC, but on an intel 8700K they play back at 60P. This is likely due to the GPU decoding that is Intel Only at the moment. Would be nice for Adobe to support Cuda decoding on the GPU so AMD users can get this speed boost.

Media info of test file:
Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High 4:4:4 Predictive@L5
Format settings, CABAC : No
Format settings, RefFrames : 1 frame
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 35 s 684 ms
Bit rate mode : Variable
Bit rate : 70.0 Mb/s
Maximum bit rate : 108 Mb/s
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 60.000 FPS
Color space : YUV
Chroma subsampling : 4:4:4
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.563
Stream size : 298 MiB (98%)
Language : English
Color range : Limited
Matrix coefficients : BT.709

Dropbox Link to file https://www.dropbox.com/s/pvxmvxyksqopqc1/2018-09-17%2000-01-17.mov?dl=0

This was encoded with NVenc in OBS studio 22. This is a 4:4:4 capture of some gameplay of counter strike.

I have this problem as well, and it drives me crazy. My machine has a 1950x CPU and GTX 1070 GPU. Constant frame dropping on playback of baseline 1080 footage, proxy footage, and even rendered footage in the timeline. Disk speed and RAM etc. is more than fast enough to handle it. I don't have an alternate GPU to test, but it sounds like Peter's AMD card bypasses the issue. This shouldn't be happening.

I wish i could rename this thread to GTX 1080 + Threadripper + Premiere = problems. Would love to hear from a dev on this issue.

@Reese I run into a lot of export problems with .mxf files. Try exporting through media encoder.

Is anyone else getting constant render failures with the H.264 unable to produce frame error? I'm pretty much unable to export any video over 5 minutes in length without first completely deleting cache files, rendering a preview and then exporting.

Moving to resolve is a no-brainer. It's modern UI & full hardware utilization are enough for the most editors.
Adobe is unable to fix their problematic code for years.
It seems that a complete software re-design is the only solution, however I wouldn't bet on that, since their competitors are way ahead.

I wish we could get an answer from adobe. I just tried putting my gtx 1080 ti card back in and still having dropped frames on basic 1080 footage. (a7s) Looks like ill have to put the 5870 back RIP

Ok I am disappointed. I have upgraded from i7-2600K (4 Cores) to Ryzen 7 2600X (8Cores) and yes there is a significant boost in realtime playback. However, 1080P footage is still lagging after adding few effects and video overlays? Wtf?

32GB RAM
3 seperate ssd drives for OS_Footage_Cache

Don't have Threadripper but having the same issue -

I'm running on Intel Core i9-7940x with 14 cores, 64GB Ram, NVIDIA GeForce GTX 1080 Ti, a separate internal SSD for cache, separate SSD for program files, and editing Panasonic EVA1 4K footage off of an internal 1TB SSD.

The program is being incredibly buggy- it will boot up fine and give me no problems for about ten minutes, then the lag will start. It starts as an annoyance but progresses to un-workable. I've tried everything in this forum :

Premiere Pro CC 2017 lag

I tried proxies...no dice.

This comes after a long string of events for us-we had a similar issue on an iMac a few weeks ago that brought us to the point of not being able to edit. We invested in a beast of a machine, tried rebuilding our projects from scratch, tried different drives at different speeds....nothing but issues! Please help!

Disregard my earlier comment. This problem does go away sometimes after o fiddle around enough with things, but it always comes back within a day or two. Glad to hear that Adobe is working on it as I really don't want to have to rebuild my system on Intel or get rid of my 1080. Let's do this, Adobe!

People are talking more and more good stuff about Davinci Resolve. I am getting an Ryzen 2700X in a couple of days and I hope for a major performance increase, compared to my current setup i7-2600K. I am struggling with Full HD playback + Couple of effects and layers. Even 1/4 is lagging.

We'll see how the timeline performance will be. But, I have heard from many creators that premiere pro isn't scaling that good with multiple core. So I give this thread +1 -> I am sure this will be very important in the future.

Update : I just chatted with support and they told me that the engineers are working on this issue and they will be releasing a patch in the near future. We shall see if and when i guess?

Anyone have a VEGA we can test? I'm having the same issues with premiere cc. 1950x/64gb ram/1080 gtx and playback/timeline is choppy. Ridiculous this isn't fixed yet. Resolve works perfectly. I've updated to latest NVIDIA/AMD drivers and did notice a slight improvement in Premiere. So is this an Nvidia/AMD issue? Will have to test further but still seeing some delayed timeline responses and chop.

Update....I pulled out the gtx 1080 and replaced with an old ATI HD 5800 series gpu and now have no dropped frames. Might have to sell my gtx 1080 and go with a vega ?

I just updated all drivers including the latest chipset drivers from AMD and the latest NVIDIA drivers. I have noticed vastly improved performance. Sometimes this can be misleading because things will be great after a reboot or something and then bog down but I have had minimal issues with several days of editing. Make sure all your drivers are supported and report back.