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Tomcat i7221 S5150
If you enable this feature, 1MB of memory (the 15th MB) will be reserved exclusively for the
ISA card's use. This effectively reduces the total amount of memory available to the operating
system by 1MB.
If you disable this feature, the 15th MB of RAM will not be reserved for the ISA card's use.
The full range of memory is therefore available for the operating system to use. However, if
your ISA card requires the use of that memory area, it may then fail to work.
Since ISA cards are a thing of the past, it is highly recommended that you disable this feature.
Even if you have an ISA card that you absolutely have to use, you may not actually need to
enable this feature.
Most ISA cards do not need exclusive access to this memory area. Make sure that your ISA
card requires this memory area before enabling this feature. You should use this BIOS feature
only as a last-ditch attempt to get an ISA card to work.
Disabled / Enabled
DRAM Data Integrity Mode
This BIOS feature controls the ECC feature of the memory controller.
ECC, which stands for Error Checking and Correction, enables the memory controller to detect
and correct single-bit soft memory errors. The memory controller will also be able to detect
double-bit errors although it will not be able to correct them. This provides increased data
integrity and system stability. However, this feature can only be enabled if you are using
special ECC memory modules.
Because present day processors use 64-bit wide data paths, 72-bit (64-bit data + 8-bit ECC)
ECC memory modules are required to implement ECC. Please note that the maximum data
transfer rate of the 72-bit ECC memory module is the same as the 64-bit memory module. The
extra 8-bits are only for the ECC code and do not carry any data. So, using 72-bit memory
modules will not give you any boost in performance.
In fact, because the memory controller has to calculate the ECC code for every data word that
is read or written, there will be some performance degradation, roughly in the region of 3-5%.
This is one of the reasons why ECC memory modules are not popular among desktop users.
If you are using standard 64-bit memory modules, you must select the Non-ECC option.
However, if you already have 72-bit ECC memory modules, you should enable the ECC
feature.
Related Options:
Non-ECC / ECC
3.5.1 PCI Express Root Port Function
This option enables the BIOS to detect the PCI devices attached to the four PCI Express ports.
PCI Express is the third generation high performance I/O bus used to interconnect peripheral
devices in applications such as computing and communication platforms. The first generation
buses include the ISA, EISA, VESA, and Micro Channel buses, while the second generation
buses include PCI, AGP, and PCI-X. PCI Express is an all encompassing I/O device
interconnect bus that has applications in the mobile, desktop, workstation, server, embedded
computing and communication platforms.
To improve bus performance, reduce overall system cost and take advantage of new
developments in computer design, the PCI Express architecture had to be significantly re-
designed from its predecessor buses. PCI and PCI-X buses are multi-drop parallel
interconnect buses in which many devices share one bus.
PCI Express on the other hand implements a serial, point-to-point type interconnect for
communication between two devices. Multiple PCI Express devices are interconnected via the
use of switches, which means one can practically connect a large number of devices together
in a system. A point-to-point interconnect implies limited electrical load on the link allowing
transmission and reception frequencies to scale to much higher numbers. Currently PCI
Express transmission and reception data rate is 2.5 Gbits/sec. A serial interconnect between
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Chapter 3: BIOS Setup
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