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Guide: AMD Athlon 64 Motherboard BIOS Settings - Advanced Chipset Features and Memory
Written by danrok   
Friday, 04 February 2005 22:25
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Guide: AMD Athlon 64 Motherboard BIOS Settings
PC Health Status
Advanced Chipset Features and Memory
CPU and Voltage Settings
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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.

advanced chipset features

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 RAM.

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.

DRAM Configuration

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.

DRAM configuration

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 overclocking possibilities.

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.

Memory Timings

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.

When 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. 

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