Mb size of a videocard

Does more mb make a videocard faster thus resulting in higher fp?
eg 8600gt 256mb vs 8600gt 512mb?

 

For the most part, there won't be a difference, unless you play certain games like Oblivion on really high resolutions that requires a larger frame buffer. However, with the case of the 8600M GT video card, the biggest impact in performance is actually the type of memory being used. There are two editions of the cards, the slower DDR2 memory, and the faster DDR3 memory. It is confirmed that having DDR3 results in a performance gain as compared to the DDR2 memory, however I have not used either of the cards myself to tell you how significant the difference is.

 

No. Clock speeds are much more important.

 

Uhm NO. The MB number ,if larger helps in higher resolutions only.
What matters in a card are the SP # , frequencies(the higher the better,preferably ddr3 or ddr4) and why not, $

 

It doesn't make a graphics card faster, it makes it capable of handling larger textures and stuff, which in turn could result in better performance in certain games.
However, there are not that many games currently out there that require more than 256MB of on board memory, so I suppose you would not see much improvement if the memory was the only difference between those cards.

But, other differences, such as clock speed and memory access speed could be significant (for example a 8600GT DDR3 will outperform a 8600GT DDR2).

 

The 8600Gt's 128-bit bus cannot utilise the full 512mb of Vram anyway.

 

Well, if it was GDDR3 1800 or 2000 it could (see 8600GTS, 8700M GT) but not at DDR2 800

 

Not really...

Memory is only really an issue if its (1) too low or (2) the bus isn't wide enough. Having a 64bit memory bus, or 64MB-128MB of memory can cripple a card because data transfers aren't fast enough. But once you get to 128+ bit buses, and 256+ MB of video memory...well, only the most powerful cards will benefit from more.