|Note||For newer Intel® graphics products, refer to Graphics Memory FAQ For Windows 8 and 8.1*.|
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What is dynamic video memory technology (DVMT)?
Dynamic video memory technology (DVMT):
- Is a concept used with Intel® graphics products.
- Dynamically allocates and de-allocates the optimum amount of memory for balanced 2D, 3D graphics, and system performance.
- Allocates the proper amount of display, texturing, and buffer memory after the operating system (OS) has booted.
- Returns the memory to the operating system when no longer required. For example, the OS views the Intel® Graphics Media Accelerator Driver (Intel® GMA Driver) as an application. Intel GMA Driver uses direct Accelerated Graphics Port (AGP) to request allocation of more memory for 3D applications. DVMT returns the memory to the OS when it's no longer required.
What are the benefits of DVMT?
DVMT ensures the most efficient use of available system memory resources for maximum 2D and 3D graphics performance.
DVMT aligns with the design guidelines for Microsoft drivers. It dynamically uses only the system memory needed and returns these resources to the operating system when finished. Some integrated graphics solutions permanently dedicate large amounts of memory. Dedicated memory ends up wasted.
What is pre-allocated memory?
Pre-allocated memory is:
- System memory the system BIOS makes available at boot time for video.
- Also known as locked memory. It's locked for video use only and invisible to the operating system.
Older Intel graphics products allow you to set pre-allocated memory in the system BIOS to 1 MB, 8 MB, or 16 MB. We do not recommend using the 512 KB legacy setting. Upon boot, the system BIOS pre-allocates the amount selected from the top of the main system memory. The 1 MB or 8 MB amount you select is dedicated for VGA/SVGA graphics.
Who sets pre-allocated memory?
The system manufacturer sets amount of pre-allocated memory via the system BIOS. Depending on the system BIOS implementation, the amount may or may not be configurable.
How do I determine or choose pre-allocated memory size?
512 K setting:
- Provided as a legacy setting only. We do not recommend using this setting.
1 MB setting:
- Allows most memory resources to go to the operating system (OS) while allowing BIOS for all modes.
8 MB setting:
- Allows a good balance between BIOS and OS-required memory resources for a 128 MB memory system.
- Enables booting Microsoft* OS in 1600x1200x32 mode without the driver having to ask the OS for more memory.
16 MB setting:
- Maximum amount allowable, and is not available on all configurations.
- We recommend only selecting on systems with over 2456 MB of system memory.
Both the 512 K and 1 MB settings assume the system boots using a Microsoft* OS.
What if an application requires more than the total amount of pre-allocated memory?
A graphics-intensive application such as a game or DVD might require more memory than the amount of pre-allocated video memory. In systems using older Intel graphics products, it communicates the need for more memory to the Intel® Graphics Media Accelerator Driver (Intel® GMA Driver). DVMT asks the operating system to supply the extra memory required. When the application no longer requires the extra memory, DVMT returns it to the operating system. The memory can repurpose as system memory.
When is DVMT triggered?
- Any time an application needs video memory above the pre-allocated amount.
- When an application no longer needs extra memory. DVMT returns the memory to the OS.
- At boot time if you set a screen resolution that requires more memory than the total amount of pre-allocated memory.
Does DVMT always get the memory requested?
DVMT may not always get the memory requested. The OS decides whether to grant more memory. DVMT allows the operating system to decide based on availability of system memory resources and other requests it receives.
How much graphics memory does DVMT use?
Graphics memory size is:
- The same as memory size in the Control Panel/Display Adapter pages.
- Also video memory used by external PCI Express* graphics cards.
- The memory dedicated for graphics for the time that the application is active and the OS has granted the requested memory.
Memory size = Pre-allocated memory + extra memory requested by the application via the Intel® Graphics Media Accelerator Driver
The maximum amount of graphics memory depends on the system BIOS configuration. In most cases, the total does not exceed 128 MB. On some older computers, the system BIOS doesn't limit the graphics memory to 128 MB. You may see maximum graphics memory up to 224 MB.
Pre-allocated memory is invisible to the operating system. When you exit the Intel® Graphics Media Accelerator Driver, the application relinquishes the extra memory it requested from the OS.
|Extra DVMT documents|
|Intel® 810 and 815 Chipset Family DVMT (PDF)|
|Intel® 82845G Graphics Controller DVMT (PDF)|
|Intel® 865G Graphics and Memory Controller Hub (GMCH) DVMT (PDF)|
|Intel® 915GM/GMS, 910GML Express Chipset Family|
Note: PDF files require Adobe Acrobat Reader*
|Frequently asked questions about graphics memory for Windows 8*/8.1*|
|Frequently asked questions about graphics memory for Windows 2000*/XP*/Vista*/7*|