Lenovo y50 4k showing 12135MB Gpu memory?? please help

i bought lenovo y50 with 4gb gtx 860 maxwell graphic but when i look through dxdiag tool it shows 12135MB memory?? whats wrong.. Please help
Heres a pic

 

Total memory = 4GB VRAM + 8GB system RAM.

 

Ram on my laptop is 16 GB

 

It's probably set in the bios to share up to 8GB of the system memory.

 

Could it be you having 860m SLI? Just saying

Regards.

 

Yeah, like Nick says. Dxdiag shows the memory addressable by windows. And for whatever reason, the formula is something like this: Shared memory (Calculated by windows as "total ram" - upper memory(512mb... ..old, unreliable convention needed for avoiding 32-bit problems when addressing large areas of ram) then divided by two) + div graphics card ram (which also is partially addressable by windows now).

So (16384-512)/2+4096->12032Mb

That leaves us 12135-12032 -> 103Mb, which should be the addressable IGP ram set in bios. Or.. probably 128Mb, minus approximately 25Mb lost in the addressing space for the frontbuffer and the graphics controller instructions.

But as you can see, the dxdiag number is not the actual addressable ram, but instead an estimate based on reported sizes. The usable 16Gb area then would be smaller by more than 512Mb, etc.

Of course.. presumably this dedicated memory area also resides in system ram. But from experience, that mapped area basically never is used beyond some 32Mb on an intel system unless you run a dedicated graphics context, though I have no idea why exactly that is. I mean, you would expect it to be used for buffers for desktop contexts, or that it would grow depending on workload - but this is again addressed in a different way, so any texture use for example is separately mapped again (likely in the marked "shared memory" area). So a guess would be that this is a standard package loaded by some firmware routine.

Windows doesn't actually use that shared memory on system ram as a rule, though. It's basically just a parameter picked by the OS that the igp will be able to map (size of this evidently was picked a decade ago, just like the default virtual memory mapping sizes). Anything that goes through the nvidia driver will always use the graphics card ram. In the same way, the intel driver actually will obey some other limitation as well, likely from necessity when avoiding overruns. Physx settings as well, preferring chipset over dedicated mapping, etc. doesn't seem to affect it..

Unfortunately, I don't know how to reduce that "shared ram size" to something more predictable. But you will likely never have the IGP ever claiming/reserving more than the size allocated by the bios-parameter. So.. just ignore it, I guess would be the best advice

 

Sometimes it's adjustable in the bios.