I've checked the forum and i saw a few other threads with an issue similar to mine, but most was on laptops with integrated graphics. and/or didn't have a resolution that worked for me. There also was one that posted his issue, but apparently never came back, but instead of stealing his thread, in case our issues aren't the same after all.
First of all. You will quickly notice that all attached screenshots say "RX580", but that seems to be a bios error from Sapphire Technologies, I've seen others with the same (seemingly minor) issue. The card i have is a RX570 8GB, if you ignore the name, then the specs match Sapphires version of the card. Link to card: http://sapphirenitro.sapphiretech.com/en/570-8.html
I used to have a AMD Radeon 7970, but it was old and started to have issues, so i recently replaced it with a brand new RX570. And all my games works fine, as expected, except for Minecraft with mods.
When i load up Minecraft, i see that once past the main menu, and trying to join a world, either local or hosted, the GPU maxes out completely, and once ingame i have 0-1 fps.
I've tried running the game in fullscreen or windowed mode, and that made no difference.
Both Windows taskmanager, and the WattMan profiler in the Radeon settings indicate that the GPU is maxed out.
Also, the Radeon settings where i added "javaw.exe" to be able to check it with WattMan calls it Star Wars, like seen in another thread too.
The modpack version for Minecraft is one i was easily able to run with the Radeon 7970, i specific went back to the version of the pack i last played to make sure it wasn't a issue with newer versions of that pack. Link to modpack (specific version used here): https://minecraft.curseforge.com/projects/all-the-mods-3/files/2559956
PS. Sorry if the images are a bit out of order, i had some issues with this editor
Since the 570 is basically a cut down 580 it's not really that surprising, what does Windows device manager read for the model?
Normally I would recommend a different driver or game update but it sounds like you're probably up to date. Does the game run alright without any mods installed? If so, I'd suggest that something in the third party modifications package is responsible for eating up GPU resources. Perhaps something like depth of field, fog, or post processing effects...
All software reads the card as a 580, including the Radeon app that comes with the driver.
I thought maybe it was the new driver i installed when i got the RX570, but being unable to remember what version i ran with the HD7970, i couldn't test that theory.
I could however swap the cards back. So, i unplugged the RX570, and plugged in the old HD7970 instead, booted up on the same driver. Started the same instance of Minecraft with all the mods. Bam. 38-40 FPS. Which is playable in my book, considering the amount of mods installed, and the limits of the Minecraft/java core.
So something weird is definitely going on with the RX570. While having Minecraft open, the task manager showed 37% load on the GPU, with the HD7970 that is.The mystery continues.
PS. No answer from Sapphire yet, i included a link to this thread in my ticket. Fingers crossed
With the RX 570 installed, can you raise the power limit in RS and adjust the fan speed curve manually in order to achieve higher playable fps? It almost sounds like a case where the software (or BIOS) is throttling the newer card at full tilt (i.e. 100% GPU usage). HD7970 uses a lot more power than RX 570 (or RX 580 for that matter) so this might be worth checking out.
I'm not sure how to do that, and wouldn't it be voiding any kind of warranty to mess with these settings, just like overclocking?.
On a side note. Sapphire support got back to me in broken English, pretty much stating they didn't care about the RX570/580 issue and closed the ticket. If they didn't make such darn good cards then i certainly wouldn't use them again.
That's a pretty crummy response from support.
Nevertheless, you can use the global wattman settings to raise the power limit on the card. This basically tells the card that it's alright to use more power if necessary to maintain adequate performance, so not really voiding any warranties. I typically run my cards at about +20% so that if there's something really taxing the card it is able to use more power than the default.
This is a bit different than forcing more mV into the core, so you don't have to worry about breaking anything.
According to TechPowerUP.com that has vBIOSes for all GPU Cards. The vBIOS for the RX 570 and RX 580 are identical. VGA Bios Collection | TechPowerUp .
Here is an example showing both RX cards vBIOS:
|Sapphire||RX 570 4 GB|
Pulse Mini ITX
|2017-03-17 02:11:00||015.050.002.001.000000||PCI-E||1244 / 1750||GDDR5||Download |Details|
|Sapphire||RX 580 4 GB|
|2017-03-08 04:03:00||015.050.002.001.000000||PCI-E||1340 / 1750||GDDR5||Download |Details|
Latest AMD RX 570 GPU Driver from AMD Download site : Radeon™ Software Adrenalin Edition 18.9.3 Release Notes | AMD
Here is how to improve the Frame Rate on your GPU card playing Minecraft: Tutorials/Improving frame rate – Official Minecraft Wiki
Frame rate (also known as fps) is the frequency rate at which a video device produces unique consecutive images called frames. Frames are still pictures that when sequence together form a fluid animation that is the basis for all moving media. Frame rate is most often expressed in frames per second (fps).
Low fps will result in a "choppy" gaming experience, as far as looking like a slideshow in extreme cases. Difficult calculations (like blowing up large amounts of TNT or spawning in a large number of mobs) can temporarily decrease the fps to a complete stop.
Note that your displayed fps might not be accurate, as the game has to render all of the information in the debug menu, so you may get an increase as soon as you close the display.
javaw.exe(the one the game uses), right click it and set its priority to high (not realtime).