Selecting a frequency higher than what the CPU manufacturer recommends may cause the system to hang or crash. See System Hangup later in this section. 58 ASUS A7V User’s Manual 4. BIOS SETUP DRAM Frequency This field determines whether the memory clock frequency is set to be in synchronous or asynchronous mode with respect to the CPU Frequency. This must be set in conjunction with CPU (external) Frequency to match the speed of your SDRAM. When you press on this field, the first available option in the pop-up menu equals the CPU Frequency you select for the previous field, and the second available option is the CPU Frequency multiplied by 4/3. To maintain and ensure system stability, DRAM Frequency is set to [100 MHz] when the BIOS setup default settings are loaded/ selected. System Performance Setting [Optimal] This function controls settings related to system memory performance. When [Optimal] is selected, DRAM bank interleave, 4k page, and burst refresh will be enabled to boost system performance. For more system stability, select [Normal]. Configuration options: [Optimal] [Normal] CPU Vcore Setting [Auto] In JumperFree mode, this field allows you to select the core voltage supplied to the CPU. Leave on [Auto] to use the CPU default setting. If you want to set it manually, select [User Define], go to the subsequent CPU Vcore field, and refer to your CPU documentation to make the configuration. CPU Level 1 Cache, CPU Level 2 Cache [Enabled] These fields allow you to choose from the default of [Enabled] or choose [Disabled] to turn on or off the CPU’s Level 1 and Level 2 built-in cache. Configuration options: [Disabled] [Enabled] CPU Level 2 Cache ECC Check [Disabled] This function controls the ECC capability in the CPU level 2 cache. Configuration options: [Disabled] [Enabled] BIOS Update [Enabled] This functions as an update loader integrated into the BIOS to supply the processor with the required data. In the default position of [Enabled], the BIOS will load the update on all processors during system bootup. Configuration options: [Disabled] [Enabled] PS/2 Mouse Function Control [Auto] The default of [Auto] allows the system to detect a PS/2 mouse on startup. If detected, IRQ12 will be used for the PS/2 mouse. IRQ12 will be reserved for expansion cards only if a PS/2 mouse is not detected. [Enabled] will always reserve IRQ12, whether on startup a PS/2 mouse is detected or not. Configuration options: [Enabled] [Auto] 4. BIOS SETUPAdvanced Menu ASUS A7V User’s Manual 59 4. BIOS SETUP 4. BIOS SETUPJumperFree Mode USB Legacy Support [Auto] This motherboard supports Universal Serial Bus (USB) devices. The default of [Auto] allows the system to detect a USB device on startup. If detected, the USB controller will be enabled. If not detected, the USB controller will be disabled. When this field is set to [Disabled], the USB controller is disabled no matter whether you are using a USB device or not. Configuration options: [Disabled] [Enabled] [Auto] OS/2 Onboard Memory > 64M [Disabled] When using OS/2 operating systems with installed DRAM of greater than 64MB, you need to set this option to [Enabled]; otherwise, leave this on [Disabled]. Configuration options: [Disabled] [Enabled] Notes for JumperFree Mode System Hangup If your system crashes or hangs due to improper frequency settings, power OFF your system and restart. The system will start up in safe mode running at a DRAM-to-CPU frequency ratio of 3:3 and a bus speed of 100MHz. You will then be led to BIOS setup to adjust the configurations. NOTE: The function: “CPU Core: Bus Frequency Multiple” is available on PCB version 1.02 and on. 60 ASUS A7V User’s Manual 4. BIOS SETUP 4.4.1 Chip Configuration (Scroll down to see more items as shown.) Onboard PCI IDE Enable [Both] You can select to enable the primary IDE channel, secondary IDE channel, both, or disable both channels. Configuration options: [Both] [Primary] [Secondary] [Disabled] Spread Spectrum Control [Enabled] Leave on default setting. Spread spectrum typically reduces system electromagnetic interference (EMI) by 8dB to 10dB. Configuration options: [Enabled] [Disabled] AGP 4X Drive Strength [Auto] Configuration options: [Auto] [Manual] AGP Drive Strength P Ctrl [C] (When AGP 4X Drive Strength set to [Manual]) Configuration options: [0] [1] [2]...[F] AGP Drive Strenght N Ctrl [E] (When AGP 4X Drive Strength set to [Manual]) Configuration options: [0] [1] [2]...[F] AGP Fast Write [Disabled] Configuration options: [Disabled] [Enabled] 4. BIOS SETUPChip Configuration ASUS A7V User’s Manual 61 4. BIOS SETUP 4. BIOS SETUPChip Configuration SDRAM Configuration [By SPD] This sets the optimal timings for SDRAM related fields, depending on the memory modules that you are using. Default setting is [By SPD], which configures the subsequent 3 items by reading the contents in the SPD (Serial Presence Detect) device. The EEPROM on the memory module stores critical parameter information about the module, such...