Intel SYS7180VE user manual CAS Latency Time, Active to Precharge delay, Dram RAS# to CAS# delay

CHAPTER 3 - BIOS SETUP

Description	Choice
CAS Latency Time
When synchronous DRAM is installed, the
number of clock cycles of CAS latency depends
on the DRAM timing. Do not reset this field
from the default value specified by the system
designer.
You can select CAS latency time in HCLK of
2/2 or 3/3. The system board designer should set
the values in this field, depends on the DRAM
installed specifications of the installed DRAM
or the installed CPU.
Active to Precharge delay
Select the precharge delay timer.
DRAM RAS# to CAS# delay
This field lets you insert a timing delay between
the CAS and RAS strobe signals, used when
DRAM is written to, read from, or refreshed.
Fast gives faster performance; and Slow gives
more stable performance. This field applies only
when synchronous DRAM is installed in the
system.
DRAM RAS# Precharge
The precharge time is the number of cycles it
takes for the RAS to accumulate its charge
before DRAM refresh. If insufficient time is
allowed, refresh may be incomplete and the
DRAM may fail to retain data.

SYS7180VE User’s Manual 35

CHAPTER 3 - BIOS SETUP

Description Choice

Memory Frequency for

Select the memory frequency for DDR200/DDR266 when install the memory with specification of DDR200, or when install the memory with specification of DDR266, or Auto define by the BIOS.

System BIOS Cacheable

Selecting Enabled allows caching of the system BIOS ROM at F0000h-FFFFFh, resulting in better system performance. However, if any program writes to this memory area, a system error may result.

Video BIOS Cacheable

Selecting Enabled allows caching of the video BIOS ROM at C0000h to C7FFFh, resulting in better video performance. However, if any program writes to this memory area, a system error may result.

Memory Hole At 15M-16M

You can reserve this area of system memory for ISA adapter ROM. When this area is reserved, it cannot be cached. The user information of peripherals that need to use this area of system memory usually discusses their memory requirements.

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