All Atom processors implement the
IA-32 instruction set; support for the
x86-64 instruction set was not added until the desktop
Diamondville and mobile
Pineview cores. The Atom N2xx and Z5xx series Atom models cannot run x86-64 code. The
Centerton server processors also support the x86-64 instruction set. As a result, the ability of an Atom-based system to run 64-bit versions of operating systems may vary from one motherboard to another. Online retailer mini-itx.com has tested Atom-based motherboards made by Intel and Jetway, and while they were able to install 64-bit versions of
Linux on Intel-branded motherboards with D2700 (Cedarview; supports maximum of 4 GB memory DDR3-800/1066, but sometimes these SoC support more than 4 GB of RAM) processors, Intel 64 support was not enabled on a Jetway-branded motherboard with a D2550 (Cedarview) processor. Even among Atom-based systems which have Intel 64 enabled, not all are able to run 64-bit versions of
Microsoft Windows. For those
Pineview processors which support 64-bit operation, Intel Download Center currently provides 64-bit
Windows Vista and
Windows 7 drivers for
Intel GMA 3150 graphics, found in
Pineview processors. However, no 64-bit Windows drivers are available for Intel Atom
Cedarview processors, released Q3 2011. However, Intel's Bay Trail-M processors, built on the
Silvermont microarchitecture and released in the second half of 2013, regain 64-bit support, although driver support for Linux and Windows 7 is limited at launch. The lack of 64-bit Windows support for
Cedarview processors has been speculated to be due to a driver issue. A member of the Intel Enthusiast Team has stated in a series of posts on enthusiast site Tom's Hardware that while the Atom D2700 (Cedarview) was designed with Intel 64 support, due to a "limitation of the board" Intel had pulled their previously available 64-bit drivers for Windows 7 and would not provide any further 64-bit support. Some system manufacturers have similarly stated that their motherboards with Atom Cedarview processors lack 64-bit support due to a "lack of Intel® 64-bit
VGA driver support". Because all
Cedarview processors use the same Intel GMA 3600 or 3650 graphics as the D2700, this indicates that Atom Cedarview systems will remain unable to run 64-bit versions of Windows, even those which have Intel 64 enabled and are able to run 64-bit versions of Linux. == Microarchitecture ==