rossrosh007 said:
Hey Maxx_power, any idea which games would utilize more than 1GB of graphics ram?
So far playing on the Acer v3-471G with 2GB, i only seen battlefield and modern warfare 3 use up to about 800MB...
Does the amount of graphics ram affect performance in relation to playing on a big screen such as a large hdmi lcd tv?
The amount of VRAM used depends on the game (textures mostly) and the resolution you play at plus the VRAM dependent quality settings, mostly anti-aliasing. So playing on a TV, it depends on the TV's resolution, and not the physical size (diagonal size). Most TV's have either 1080p or 720p compatible resolutions, which means that the most frequently used TV resolutions are 1920x1080 and 1280x720. The VRAM usage of the TV in either case is identical to when you use a monitor and use those same resolutions. The VRAM usage (as well as other portions of the GPU), depends on the resolution (when the game is fixed) and not at all what interface (DVI, VGA, HDMI, etc) you use.
To be able to use all that VRAM (2GB), you must be able to use that information stored in the VRAm quickly (say, textures). So if you are sampling a large amount of textures for anti-aliasing, and the texture that needs to be stored in the VRAM doubles, so suppose that you are using 1GB originally, but with AA, you are now using 2GB, the capacity is not a problem, since you have 2GB, but whether or not you are able to use that capacity at a quick speed determines your frame rates. Doing AA requires a lot of render back end operations (usually NOT related to shaders) like ROPs and TMUs, if you have only so many ROPs and TMUs (particularly limited in the case of lower end cards), then you can only sample those stored textures in VRAM so fast. So although you HAVE 2GB of vram to store those textures, you CAN'T make use of them fast enough because the GPU haven't enough BASIC rendering resources (not shading).
The same thing happens when the VRAM is particularly slow. In that case, the GPU is fast because it has a lot of functional units, but can't get access to information stored in the VRAM fast enough, due to the slow speed of the VRAM relative to the GPU processing speed.
BOTH of these happens (most of the time) when you see something like a 76xx, 66xx, even 77xx (or equivalently, the <660 Nvidia models) series of cards coupled with >1GB of VRAM. Since in most cases, the vendors increase the amount of VRAm, but reduce the speed, which usually means changing from GDDR5 (quad data rate) to DDR3 (double data rate), and dropping speeds some what, meaning you usually have <1/2 the memory bandwidth of a 1GB card with GDDR5. It is a marketing attempt to lure people to larger numbers.
Lastly, any game that can use >512MB of VRAM has the POTENTIAL to make use of >1GB of VRAM, if you really turn up the texture resolutions (if you have that setting), and/or turn up the AA. BUT, as I have said above, whether or not that extra VRAM is beneficial to you, depends on the resolution, the speed of the VRAM, the number of render back ends in the GPU (usually ROPs+TMUs), the way the game makes use of the GPU (balance of shader and render back end operations).
Vendors usually get away with using DDR3 VRAm where GDDR5 should be used for optimal performance in laptops (and portables, all-in-ones) because:
A) The resolution of the panels are LOW in consumer laptops (~720p/ most common), so the VRAM speed drop is not as noticeable (as resolution is low).
B) Slower speed VRAM uses less power, even if the capacity is twice that of the faster VRAM. DDR3 and GDDR5 at the same base frequency has a power consumption that is higher with GDDR5 (they operate at similar voltage ranges).
C) It is just plain cheaper, and most won't notice until....