Vram not full before using shared vram

[HeyLittleBitty]

Vram never gets full before using Shared GPU memory. I have a MSI RX6600 with 8.0 GB of Dedicated GPU Memory. Any games I play that need to start using more Vram will slow down heavily the moment my Vram goes around 7.2GB usage. I have 4x8GB, 32GB of Ram (16.0 GB of Shared GPU Memory) but its not very fast, 3000Mhz.

Games will show maybe slightly less like 7.9GB to 7.6GB. GPU-z shows 8192MB. 

I even booted up 2 different games but it still didn't use it.

I don't know if the amount windows uses is calculated together with the rest of the programs when calculating 7.2GB usage.

Can someone tell me why my PC doesn't use the rest of the Dedicated GPU Memory? Its kinda annoying to think that my PC decides not to use the rest of the VRAM or that I may have faulty gpu?

[Eigenvektor]

8 minutes ago, HeyLittleBitty said:

Games will show maybe slightly less like 7.9GB to 7.6GB. GPU-z shows 8192MB.

Might be the amount of VRAM the game has available for textures, discounting other things it has already loaded into memory. How are you monitoring VRAM usage while in game?

 

Also, which games are you talking about? I've also got an RX6600, so might be able to compare if I happen to own one of them. If there's not enough VRAM, best course of action is probably to lower texture details.

[HeyLittleBitty]

8 minutes ago, Eigenvektor said:

Might be the amount of VRAM the game has available for textures, discounting other things it has already loaded into memory. How are you monitoring VRAM usage while in game?

 

Also, which games are you talking about? I've also got an RX6600, so might be able to compare if I happen to own one of them. If there's not enough VRAM, best course of action is probably to lower texture details.

I have used Task Manager, Radeon Software and MSI Afterburner and they all said the same.

For example, Monster Hunter: World, Horizon: Zero Dawn, Lords of the Fallen. 

MHW and HZD claimed I had around 7.6GB to use, but neither ever got passed 7.2GB despite more being "available" and "required".

I've seen YT vids of people using more than 8GB Vram usage on Lords of the Fallen yet mine also never got passed 7.2GB vram usage with any settings.

For HZD, textures will literally start popping in and out when at 7.2GB usage, over time or when I start up a browser or other applications, the 7.2GB usage stays and the game will literally remove almost every texture in the game, torso gone, plants gone, polygonal characters etc. then crash.

I've been playing with lowered textures because of the "imaginary" 7.2GB VRAM cap my PC has.

[Dr. Will0hlep]

Okay, not an expert on this at all... it is completely outside my bubble of knowledge... and I have no idea if I'm just talking shit here but... My theory is that the 0.8GB of free space in your Vram is not contigous (in one place), but instead split up into much smaller chucks. This means that when your PC wants to load something new into Vram (while Vram is already nearly full) it will have to move the things currently stored in Vram around first to make room, for the new stuff. This leads to stuff being pushed to your RAM while your VRAM finds new homes for it.

 

However, I reiterate, this theory might be rubbish.

[Bagzie]

1 hour ago, will0hlep said:

Okay, not an expert on this at all... it is completely outside my bubble of knowledge... and I have no idea if I'm just talking shit here but... My theory is that the 0.8GB of free space in your Vram is not contigous (in one place), but instead split up into much smaller chucks. This means that when your PC wants to load something new into Vram (while Vram is already nearly full) it will have to move the things currently stored in Vram around first to make room, for the new stuff. This leads to stuff being pushed to your RAM while your VRAM finds new homes for it.

 

However, I reiterate, this theory might be rubbish.

For someone who claims not to have much knowledge what you suggested seems atleast plausible to me. Then again I don't know anything either  

[Eigenvektor]

1 hour ago, will0hlep said:

This means that when your PC wants to load something new into Vram (while Vram is already nearly full) it will have to move the things currently stored in Vram around first to make room, for the new stuff.

That sounds plausible, especially for open world games like HZD that are constantly streaming new data into VRAM and delete things no longer needed as you move through the world. Though I would hope they'd do it in a way that avoids too much shuffling around.

 

It's been a while since I last played that game, but I don't remember it slowing down over time or running into any VRAM issues on my RX 6600. Though not sure if it would restore my graphics settings if I reinstalled it for reasons of comparison.

[HeyLittleBitty]

update: So the actual usage apparently is 7.5GB usage according to Radeon Software. DxDiag says i have 7.8GB available.

I disabled AMD SAM, which uses some more Vram, and tested Watch Dogs 2 on everything ultra, pixel density, extra objects etc. The game ran smoother than before, but still stopped at 7.5GB. so it helped kinda, but its still not using the full amount of Vram like other people's gpu, exact same gpu. theirs can go to ~8GB usage. 

[NobleGamer]

VRAM usage is largely a black box, because evidently whatever Windows and most other apps like Afterburner use is actually VRAM allocated, not necessarily how much is actively in use or is holding data that will be used.

 

I think Intel might working on a tool that helps unlock some of these mysteries, but it's been quite a while since I saw something about it on YouTube, perhaps from GN?

 

I've experienced a similar issue with trying to use a 10 GB AI model with my 10GB 3080, and the AI app says I'm ~1 GB short too.

 

Could be the dumb difference between gigabytes/gigabits/etc, could be that some VRAM is always reserved by the GPU hardware/firmware for other stuff, etc.

[HeyLittleBitty]

Ok! So I found reason why the PC wouldn't seem to go higher than 7.5~GB. 

The setting "10-bit Pixel Format" was needing more VRAM. especially with my 1440p monitor...

As soon as I disabled it, I was able to use around 7.9GB Vram.

With AMD SAM turned off I was able to hit 8GB usage.

I might keep SAM enabled since the impact is minimal.

I don't think I'll notice the color difference between 8bit color and 10bit anyways.

Still annoying that the VRAM wasn't being shown as used by any program. should've just been calculated with the rest from the start.