AR-B1641 User’s Guide
26
DRAM Refresh:
This option specifies the refresh rate frequency for the installed system memory SDRAM DIMMs. If you
have good quality of DRAM, you can choose longer refresh rate to get better system performance.
DRAM Cycle time (SCLKs):
Select the number of SCLKs for an access cycle. The setting are:5/7 and 7/9.
CAS# Latency (SCLKs):
This controls the timing delay (in clock cycles) before SDRAM starts a read command after
receiving it. Settings are 3 Clocks and 2 Clocks. 2 Clocks increases the system performance while 3 Clocks provides
more stable performance.
SDRAM RAS# to CAS# Delay (SCLKs):
This field allows you to set the number of cycles for a timing delay between the
CAS ans RAS strobe signals, used when DRAM is written to , read from or refreshed. Fast speed offers faster
performance while slow speed offers more stable performance. Settings: 3 Clocks and 2 Clocks.
SDRAM RAS# Precharge (SCLKs):
The field specifies the idle cycles before precharging an idle bank. Settings: 7
Clocks, 6 Clocks and 5 Clocks.
Internal Graphics Mode Select:
This setting allows the Internal Graphics mode to be modified. The Optimal and
Fail-Safe default settings are Enabled, 1MB.
Option
Description
Enabled, 1MB
This option allows the Internal Graphic controller to allocate 1MB of system memory
for video display use. This is the default setting.
Enabled, 512KB
This option allows the Internal Graphic controller to allocate 512KB of system
memory for video display use.
Disabled
This option allocates no system memory for video display use.
Display Cache Window Size:
This setting allows the Display Cache Window Size to be modified. The Optimal and
Fail-Safe default settings are 64MB.
Option
Description
32MB
This option allows caching of up to 32MB.
64MB
This option allows caching of up to 64MB. This is the default setting.
AGP Aperture Window:
The field selects the size of the Accelerated Graphics Port( AGP) aperture. Aperture is a
portion of the PCI memory address range dedicated for graphics memory address space. Host cycles that hit the
aperture range are forwarded to the AGP without any translation. Settings are 4MB, 8MB, 16MB, 32MB, 64MB, 128MB
and 256MB.
Local memory Frequency:
This item allows you to select the Memory Frequency.
Initialize Display Cache Memory:
This option will enable or disable Local Memory (Display Cache) and UMA capable.
Settings are Enabled and Disabled.
Paging Mode Control:
Display cache paging mode. Settings are Open and Closed.
RAS-to-CAS:
This field allows you to set the number of cycles for a timing delay between the CAS and RAS strobe
signals, used when DRAM is written to , read from or refreshed. Fast speed offers faster performance while slow speed
offers more stable performance.
CAS Latency:
This controls the timing delay before SDRAM starts a read command after receiving it.
RAS Timing:
This item controls the timing for RAS. Settings are Fast and Slow.
RAS Precharge Timing:
This item controls the number of cycles for RAS to be allowed to precharge. Settings are Fast
and Slow.
CPU Latency Timer:
During Enabled, A deferrable CPU cycle will only be Deferred after it has been in a Snoop Stall for
31 clocks and another ADS# has arrived. During Disabled, A deferrable CPU cycle will be Deferred immediately after the
GMCH receives another ADS#.
USB Function:
This option will enable on-chip USB function to support USB (Universal Serial Bus) peripheral devices if
user chooses the “Enabled” setting.
USB Device Legacy Support:
This field supports Universal Serial Bus (USB) devices. If detected, USB controller
legacy mode will be enabled. If not detected, USB controller legacy mode will be disabled.
Port 64/60 Emulation:
Setting this option to allow a USB keyboard to act like a legally keyboard.
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