Does a paltry 256MB of RAM matter? Apparently, it does, if you’re talking about Nvidia’s GF104-based GTX 460 cards.
In the October issue, we took a long look at Asus’s sweet GTX 460 768MB card. While that card impressed us for the most part, it did seem a little weak in a few areas, especially when you turned up antialiasing. This 1GB version isn’t just the same chip with another 256MB of GDDR5 memory slapped on.
The memory bus is actually wider than the 768MB card, at 256 bits wide instead of 192 bits wide. That extra bus width is managed by a fourth memory controller on board the chip (the 768MB card has only three memory controllers.) If you’re thinking that the 1GB version of the GeForce GTX 460 should have had its own model—perhaps GTX 463—you’re not alone. A lot of people have wondered why Nvidia would use the same nomenclature for these two different beasts. The chip itself is the same. The 1GB chip is based on TSMC’s 40nm process technology, and has the same 1.95-billion transistor count as the 768MB version.