Originally Posted by kevinqian
So you see 3.68gb usable out of 4gb? hmm seems like an Intel gpu issue. Why would BIOS reserve more than the 128mb allocated to the IGP?
I think you are still off on the concept of that usable number. That number includes any memory dynamically allocated by Windows. What's taken away by the BIOS, windows has no control over. Open "Resource monitor", you will see under "Hardware reserve" 332MB. You will notice, that number does not change under heavy gpu load, it's the baseline minimum allotted to the gpu regardless of gpu load.
There's really no issue at all. The BIOS yanks away 128mb immediately, and does not at any time give it up. The video card needs memory to start with, and if it ever loses it then your video goes away, so you've got an absolute minimum of 128mb being utilized. Windows allocates the additional RAM for tasks, and will increase/decrease it as it needs to, not unlike your page file (AKA virtual memory). The memory is used to buffer video information, and with the amount of information we're feeding it (ie HD video) it only allocates what it can use; allocating a full 1gb doesn't do any good becuase by the time it will run down the buffer it could have been refilled several times (not to mention hogging it away from the system), but it will increase beyond the baseline 128mb because it needs more for what's going on right now (Aero, video playback).
Sort of like how you wouldn't go buy ten gallons of milk at once for a family of four, but you need more than just an 8oz carton at a time. The ten gallons will go to waste, but you need more than that 8oz because you'll need to go run to the store several times a day. The buffer HAS to have that 128mb, but allocates the additional memory so it's got enough to not be going crazy, but isn't eating up all of your system RAM.
In short, don't worry about it. Best case is that you're getting exactly what you need like everyone else (which is good), and worst case is that it's eating up up to 256mb too much. And even that "worst case" is not a big deal.