More Memory, Please
When you make the jump to a 64-bit ecosystem—and by that I mean a 64-bit processor on a motherboard with an aware BIOS (pretty much everything nowadays), a 64-bit operating system, and the requisite 64-bit drivers, the memory ceiling theoretically jumps to an astounding 16 exabytes of RAM—17.2 billion gigabytes. Realistically, processors, chipsets, and motherboards bring maximum capacity, even in a 64-bit environment, down to more familiar levels. A lot of the X58-based boards we’ve been looking at, for instance, top out at 24 GB of DDR3 memory.
In addition to increasing the amount of physical memory space available, stepping up to 64-bit also augments the virtual address space that was so limited in 32-bit environments.
|Application Type||Virtual Address Space|
|Standard 32-bit||2 GB|
|Large Address Aware 32-bit||4 GB|
|Native 64-bit||8 TB|
As the chart indicates, running a standard 32-bit app on your 64-bit OS will still limit you to 2 GB of virtual address space (collective groan from the peanut gallery—most gaming titles are still 32-bit-only, including most of the titles we run as benchmarks). Applications written to be aware of large addresses (those with the /LARGEADDRESSAWARE linker flag) support up to 4 GB without any special boot mode. And native 64-bit apps get up to 8 TB of virtual address space—and Microsoft says it can increase that number without impacting the OS or applications when the need arrives.
The desire to shift away from the first type of game, standard 32-bit, is immediate and pressing. Indeed, it was an issue even before 64-bit operating environments became pervasive. I remember battling it out on some intense eight-player maps in Command and Conquer: Generals where, at a certain point late in the game, the app would simply run out of address space and completely fold. That had to have been sometime in 2004. The guys over at AnandTech wrote about a similar situation they experienced in Supreme Commander back in 2007. Given the very known nature of these virtual address space limitations, you’d think that game developers would be taking a more hurried approach to making the transition.