Understanding Memory - SQL Server 2012 Internals and Troubleshooting - page 55

cost-effective storage space. Consequently, servers use a combination of hard disks to store data,
which is then loaded into RAM where it can be worked with much faster.

By way of comparison, throughput for RAM modules is measured in gigabytes per second (GB/s)
with nanosecond (ns) response times, whereas hard disk throughput is measured in megabytes per
second (MB/s) with millisecond (ms) response times. Even solid-state storage technology,
which is much faster than traditional disk, is typically still measured in MB/s throughput and with
microsecond (μs) latency. You can read more about storage in Chapter 4.

NOTE Just to be clear on the relationship between the time units mentioned
here, a millisecond is a thousandth of a second (0.001 seconds), a microsecond is
a thousandth of a millisecond (0.000001 seconds), and a nanosecond is a
thousandth of a microsecond (0.000000001 seconds).

Maximum Supported Physical Memory
For ease of reference, Table 3-1 shows the maximum usable RAM for SQL Server 2012 by feature
and edition.

TABLE 3-1: SQL Server 2012 Usable Memory by Edition and Feature

EXPRESS
W/ADVANCED
SERVICES

BUSINESS
INTELLIGENCE FEATURE ENTERPRISE STANDARD WEB EXPRESS

Database
Engine

Windows
Maximum

64GB 64GB 64GB 1GB 1GB

Analysis
Services

Windows
Maximum

Windows
Maximum

64GB N/A N/A N/A

Reporting
Services

Windows
Maximum

Windows
Maximum

64GB 64GB 4GB N/A

http://msdn.microsoft.com

SQL Server 2012 Enterprise Edition and SQL Server 2012 Business Edition support the maximum
RAM of the underlying operating system, the most popular of which at the time of writing are
Windows Server 2008 R2 Standard Edition, which supports 32GB, and Windows Server 2008 R2
Enterprise Edition, which supports 2TB.

Windows Server 2012, due for release at the end of 2012, supports a maximum of 4TB of RAM.