This is a brief guide on how graphics memory works and is reported in Windows 7. There has been much confusion here and elsewhere with this due to how things are worded when looking at the detailed report from a WEI score for example,
Looking at the numbers above it would appear that there is a total of 2303 MB of video memory, however that isn't the case. To break it down and make it easier to understand you need to realize what the three variables listed are,
Dedicated graphics memory
This is the actual amount of physical memory that the video card will have, whether it is onboard or a dedicated video card. For most onboard video this value is what is allocated in the bios and deducted from the total of the system ram, and cannot be changed from within Windows. For a dedicated card this is physical ram on the card and cannot be upgraded like system ram can.
Dedicated system memory
This is mainly seen on Intel graphics solutions as seen here,
Another thing with the current generations of Intel graphics is that the amount of graphics memory is dynamic, meaning that the graphics run on the base amount as shown above but will increase as needed (and also lower the amount of available system ram at the same time).
Shared system memory
This is the number that throws a lot of people off. It is more like a pagefile for the video card, also known as "Virtualized video memory",
and is a total of graphics memory and total system ram. What it doesn't do is take anything from system memory unless the full amount of graphics memory has been used, and then will only use what is required and release it once it is no longer needed.
The new Microsoft Windows Vista Display Driver Model (WDDM) brings fundamental changes to the management of graphics memory in a system.
Prior to Windows Vista, graphics memory was reported by the graphics driver as a single number through the Display applet in the control panel. Some legacy APIs exposed two types of memory: local and non-local. However, these numbers were selected by the driver and were mostly inaccurate.
With the introduction of Windows Vista, the operating system is putting a much heavier load on the GPU than ever before. Overall system performance is now closely associated with the graphics subsystem performance and is directly affected by the amount of graphics memory available. Microsoft is enhancing how graphics memory is reported, so that end users can better understand the factors that directly impact the system performance. With WDDM, Windows Vista can accurately account for each of the graphics memory contributors and report available memory precisely through new APIs.
It's important for software running on Windows Vista to be able to accurately determine the amount of available graphics memory. WDDM manages the virtualization of graphics memory in itself and also ensures accurate reporting of various aspects of graphics memory. Application developers and software vendors are encouraged to take advantage of the DirectX 10 API for retrieving the accurate set of graphics memory values on systems that have WDDM drivers.
There is also a white paper on the above link for those interested in exactly how this number is determined. There is more about the changes made to how video memory works in Windows 7 here,
System Manufacturer/Model Number Home built OS Windows 7 Ultimate 32 bit CPU Intel(R) Pentium(R) 4 CPU 3.00GHz Motherboard ASUS P4P800-VM Motherboard Chipset: Intel 865G + ICH5 Memory 2.50 GB RAM Graphics Card NVIDIA GeForce 7600 GS Sound Card SoundMax Integrated Digital Audio (Chip) Monitor(s) Displays ViewSonic VX 1962 wm Screen Resolution 1680 X 1050
Keyboard Microsoft Comfort Curve Keyboard 2000 v10 USB Mouse Logitec optic USB Cooling Fan based Hard Drives Seagate Barracuda 7200.10 80 GB
ST380215A ATA Device 18.6 GB
Western Digital "My Book" external hard drive 750 GB Internet Speed 3.01 Mb/s download 0.64 Mb/s upload
Computer type Laptop System Manufacturer/Model Number HP ENVY 17-1150eg OS Windows 7 x64 Ultimate CPU 1.6 GHz Intel Core i7-720QM Processor Memory 6 GB Graphics Card ATI Mobility Radeon HD 5850 Graphics Sound Card Beats sound system with integrated subwoofer Monitor(s) Displays 17" laptop display, 22" LCD and 32" Full HD TV through HDMI Screen Resolution 1600*900, 1680*1050 and 1920*1080
Keyboard Logitech diNovo Media Desktop Laser (bluetooth) Mouse Logitech MX1000 Laser (Bluetooth) Hard Drives Internal: 2 x 500 GB SATA Hard Disk Drive 7200 rpm
External: 2TB for backups, 3TB USB3 network drive for media Internet Speed 50/10 Mbps VDSL Antivirus MSE, Windows Defender Browser Maxthon 3.5.2. Other Info Windows 7 Ultimate Retail Full in English, additional Guest-user accounts in Finnish, German and Swedish (Working languages English & Swedish, Family language German, my own language, mother tongue, Finnish. I really need Ultimate to get to use Language Packs!)
This is the number that throws a lot of people off. It is more like a pagefile for the video card, also known as "Virtualized video memory",
and is a total of graphics memory and total system ram.
this is not true,
Shared system memory is Virtualized video memory taken only from system ram ........
Dedicated graphics memory - 512mb - real memory on your video card Shared system memory - 1791mb - additional memory taken (wiil be taken if necessery) from system ram ------------------------------------------------------ Total available graphics memory: 512 + 1791 = 2303mb
