Technical video memory question.

[monmon238]

hay there,
i wanted to ask if the increasing the memory of the video card through the computer ram,works the same as buying a card which has the high memory on board?
for example,there are two versions of the gigabyte Geforce 7300 gs ,there is a 128 MB version and a 256 MB version and they both can be increased to 512 using the computer RAM,so if i bought the 128 MB version and increased it to 256 using the computer memory, will it work the same as the the one which has the 256 MB on board?
thanks in advance.

[RA1D]

i've never heard of this

[gvblake22]

What they are talking about is an nVidia feature called TurboCache; this is just essentially shared memory. The video card can allocate a portion of your system memory for its own use. The problem with this is that the system memory is actually a little slower than the memory on the video card its self (because it has to go through the memory controller and half-way across the motherboard to communicate with the RAM). Notice also that you don't see such a feature on anything other than low-end or budget mid-range cards.

The other problem is that the low-end and budget mid-range cards this feature is implemented on have relatively low 3D gaming performance, which is the only time when extra video memory would really help. But even high-end cards have a negligible performance increase with added video memory. So as you can imagine, the extra "TurboCache" memory of the 7300GS is prettymuch worthless and just sucks up your available system memory that could be available for other more beneficial things. Overall, it is kindof a gimmick. If you are looking for a low-end entry level video card, don't plan on doing much (if any) 3D gaming on it and look for a card with the lowest amount of the "TurboCache" (or "HyperMemory" if you are looking at an AMD/ATI card).

[Lead Head]

Usually that "TurboCache" or "TurboMemory", whatever, just uses system ram like Blake says. Most computers will typically have a memory bandwidth of 4,000-14,000 MB/s, while Video Card RAM will often be much higher, as much as 70,000MB/s, and ATI's Radeon x2900 has a RAM bandwidth of over 100,000MB/s. So performance can be hit by quite a bit, but often that feature is on low end cards, like what Blake said to.