Adrian Wong from Adrian’s Rojak Pot has updated its BIOS Optimization Guide yet again. Revision 6 of the extensive BIOS tutorial is now available on line. In 17 pages Adrian explains the most common options in a simple way, and where possible he also indicates the optimal setting for the relevant option. With this tutorial at your side, you can spend an afternoon working with your BIOS to get the perfect adjustment between stability and performance. The tutorial is available in HTML, LIT and PDF format:
SDRAM CAS Latency Time
Options : 2, 3
This controls the time delay (in clock cycles – CLKs) that passes before the SDRAM starts to carry out a read command after receiving it. This also determines the number of CLKs for the completion of the first part of a burst transfer. In other words, the lower the latency, the faster the transaction.
Note that some SDRAM modules may not be able to handle the lower latency and will become unstable and lose data. Therefore, set the SDRAM CAS Latency Time to 2 for optimal performance if possible but increase it to 3 if your system becomes unstable.
Interestingly, increasing the CAS latency time does have an advantage in that it will enable the SDRAM to run at a higher clockspeed, thereby giving you an edge in overclocking your system. So, if you hit a snag while overclocking, try increasing the CAS latency time.