Guys I have a brand new Sapphire R9 390x and it has a VRAM of 8gb but when I turn on my pc it only shows 4gb.

Solution
Yes your VRAM is 8GB. This wouldn't be the first time CPU-Z has gotten this information wrong. In fact as I mentioned, only a few days ago someone had exactly the same issue with a different (but new series) graphics card. Rest assured, you have 8GB, and the author of CPU-Z will eventually catch up his software to correctly display the amount of VRAM.

I'm not sure why the other method I had you try, displayed the wrong amount VRAM. I think CPU-Z displays the information about your graphics card via the device ID. So if the author has the wrong information for that device string, he'll have to fix it. However if author is using some built in method to specifically test how much available VRAM there is, the method I suggested (via...


That part I can address: cards these days have a passive cooling mode - when temperatures are below a certain level (and therefore safe) it switches off the fans to save on power and unnecessary card wear.

When the card heats up, the fans come on automatically.

Try a game or some other high-graphic-intensity function to get the fan going a bit and see that the fans do come on after a time...
 


Would take a while before I can try this because my rig is new.
 


At first I used "dxdiag" it stated my total approximate memory is 4gb then looked at the screen resolutions advanced setting and it stated that the total available graphics memory is 8gb = 4gb dedicated video memory 4gb Shared system memory. I still don't know what that means.
 


Read the Sapphire R9 390x spec and overview and it was stated that they have intelligent fan control meaning that 1 or more fans stop when under light load and automatically restarts when temperature rises, so, I think you're right.
 
Just had a thread answered not long ago about this. Don't trust CPU-Z, it may not have the correct information about your card. You can make sure you have the latest version, but if it still reports 4GB, then it's still hasn't caught up to the new card's specs.

Did you try the link I provided?
 


I tried the link and it recommend CPU-Z but the first method said I have 8gb total memory 8gb = 4gb shared 4gb dedicated. I don;t know what those are.
 
That's odd, under Advanced, it should have shown 8GB dedicated, 4GB shared, 12GB total. For instance my 980 shows 4GB dedicated, 8GB shared, 12GB total.

I believe the shared memory is actually a portion of your systems memory that is allocated for sharing with the graphics hardware. It dates back to AGP (Accelerated Graphics Port) along time ago. It allows for fast exchange of data between the CPU and GPU.

 


So do I have 8gb usable or 8gb but 4gb usable?
 


Yes 16gb of RAM. I just Play CoD: Advanced warfare and it said that I had 6gb dedicated memory.
I installed GPU-Z and it also showed 8gb total VRAM.
 


Did that and the dedicated memory turned to 8169mb so it's 8gb now. So my VRAM is really 8gb?
 
Yes your VRAM is 8GB. This wouldn't be the first time CPU-Z has gotten this information wrong. In fact as I mentioned, only a few days ago someone had exactly the same issue with a different (but new series) graphics card. Rest assured, you have 8GB, and the author of CPU-Z will eventually catch up his software to correctly display the amount of VRAM.

I'm not sure why the other method I had you try, displayed the wrong amount VRAM. I think CPU-Z displays the information about your graphics card via the device ID. So if the author has the wrong information for that device string, he'll have to fix it. However if author is using some built in method to specifically test how much available VRAM there is, the method I suggested (via Change Resolution > Advanced Settings) maybe what is being used and would explain why both show 4GB. In this case it might be a problem with how Windows queries the amount of VRAM.
 
Solution