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Advanced Chipset Features
Here we will take a look at features including AGP and memory
settings. Bear in mind that this guide is based upon an AMD 64-bit
platform and some of these settings may only be found on systems of
this type, HT frequency for example.
AGP Aperture Size
The AGP aperture size is specified in mega-bytes. This provides
extra work space for the graphics in system memory. In a system with
ample RAM and a 64MB graphics card this could be set to 64MB. However,
when using graphics cards with say 256MB, setting the AAS to 256MB
might harm overall performance because applications could be left with
too little system memory. It is just a case of getting the right
balance according to physical memory available.
Note that AGP settings will have much the same function on all systems, not just 64-bit boards.
Should you need further help, then ask for it in
AOA's graphics hardware topic.
AGP Fast Write
When enabled the CPU will write directly to the graphics card.
Expect to see a performance increase with graphics when fast write
is enabled. The graphics card must support this feature, otherwise
crashes may occur. Be aware that fast write can cause issues, so test
the system after enabling it.
AGP Side Band Address
When enabled, SBA allows 8 extra address lines to be used in
addition to the main 32 lines. This should give a performance benefit,
however stability tests need to done. This feature helps to give AGP a
performance edge over PCI slots.
HT Frequency (AMD64)
HT is AMD's Hyper Transport technology and is found on AMD 64-bit
platforms. In depth documents explaining this technology are available
to download from AMD's website.
In this case the frequency can be adjusted via a multiplier of 1, 2,
3, or 5. For example, 4x 200Mhz = 800MHz. The maximum stable speed for
the HTT will be dependant on the hardware used and settings available
in the BIOS. Higher HTT speeds allow greater bandwidth between CPU and
In simple terms, HTT supercedes the Front Side Bus.
64-bit topic is here.
System BIOS Cacheable
Enabling this will place the BIOS in to system memory for faster
access. It is unlikely to be of any real benefit it modern systems or
may even harm performance, hence I have it disabled. Only of use on
systems running old operating systems.
This sub-section allows configuration of the RAM speed and timings.
It is important for these settings to be correct to avoid crashing. It
is a good idea to have all the exact details and specifications for the
memoery modules to hand before changing any specifications. There will
be occasions where all the automatic settings simply do not work, so a
little understanding of memory is needed.
Max Memory Clock (Mhz)
This setting can be used to force a set speed upon the installed
memory sticks. So, you could limit some 200Mhz RAM (DDR400) to a speed
of 166MHz (DDR333).
This setting comes in useful when
overclocking, it is in effect a memory divider. Any increase on CPU Mhz
will be reflected here, regardless of the limit set. Meaning that the
memory and CPU can be run asycronously giving more flexibility with
If not overclocking the 'auto' setting should serve best.
Screen-shot taken on a EP-9NDA3+ motherboard, may vary on other systems.
1T/2T Memory Timing
This relates to commands per clock (CPC). The 1T option is faster, however
cheaper memory may not be able to run stable at this speed. When
overclocking with quality memory it may be necessary to change to 2T at
higher speeds. When trouble shooting memory set this to 2T.
Timings such as CAS or Trp, for example, are specific to the memory
modules installed. RAM with low latency timings will be faster than RAM
with higher timings running at the same clock speed, e.g. DDR400.
It is possible for the BIOS to use a set of timing tables which are
stored on the memory modules, this is known as 'by SPD'. Alternatively,
timings can be entered by hand on this screen. The correct stock
timings for branded memory can be found on the vendor's website or
printed on the sticks.
overclocking the memory speed it is likely that slower timings will
need to be used. A case of 2 steps forward and 1 step back, if you
like. If overclocking the memory use a tool which will measure
bandwidth to ensure that the settings being used are actually faster. A
certain degree of personal preference comes in to play here.