I just bought a HP laptop which has a Radeon HD 3200 integrated graphics chipset - the website said it could use up to 512mb RAM, which is fine for what I want. Unfortunately there are a few things I don't quite understand:
1) It's currently set to use 256mb RAM and there's no BIOS option that lets me increase this to use the full 512. Nowhere on the system can I find an option to change it from 256 to the full 512.
2) When I look at the settings, it shows as taking 1403mb of the 4gb total RAM on the laptop, and holding it as "available graphics memory" - it's then using 256mb of this and the there's another 1150mb showing as "shared system memory" which doesn't appear to be available to the rest of the system. In case that sounds unclear, there's a screenshot here showing the graphics screen and here showing system memory breakdown.
As a result of #2 it looks like I have a laptop which has 4gb of RAM and an ingegrated chipset shich SHOULD use up to 512mb for graphics, but it's currently only got 2.8gb of RAM available for system usage, a 256mb graphics chipset, and 1gb+ of RAM sitting around doing nothing.
When I google the chipset it says it has up to 1403mb graphics memory, which fits with the figure I have showing, but nowhere does it explain how to increase it to use 512mb rather than the current 256mb, nor what the rest of the 1403mb is actually used for (if anything).
It's a long while since I read up on IGPs so I may be missing something obvious - can anyone help?
Well, that's ATI's hyper memory, kinda like nVidia's Turbo Cache. With their GPUs it basically tells the OS that it has double the RAM it really has. Half of that reported RAM is actually maped to system memory. Once the dedicated RAM it reserves some of the system RAM and treats it in a semi-dedicated matter. This allows it to pull in data faster and have a consistent area to swap vRam with data that is immediately relevant with that which is not.
For your particular IGP it is only setting asside 256MB of system RAM. When that gets full it can request the rest from the OS and once it gets it then it treats that RAM as though it were its own dedicated RAM. It allocates this automatically and with the newer drivers I haven't found a way to change the amount. You use to be able to edit some registry keys, but newer driver revisions seem to ignore those .
Nope, not really, unfortunately. Like I said it pretty much does it on demand. If an app needs more VRAM then the driver will ask the OS. If the RAM is free, or being occupied by system services that aren't constantly running and can be cached to the hard drive, then it will free up that RAM and hold it just for the IGP. If your system needs that RAM because you have too many Youtube videos open and your GPU isn't using it, then the drivers are suppose to give that RAM back to the system and then will try to get it back first chance it gets .