I couldn't find anything about PCIe lock but this is from my manual about RAM in my Bios:
DRAM Timing Selectable
This item allows you to select the value in this field, depending on whether
the board using which kind of DDR DRAM.
Ø The Choice: By SPD or Manual.
CAS Latency Time
When synchronous DRAM is installed, the number of clock cycles of
CAS latency depends on the DRAM timing. Don't change this field from
the default value specified by the system designer.
Ø The Choice: Auto,3,4,5 or 6.
DRAM RAS# to CAS# Delay
This field lets you insert a timing delay between the CAS and RAS strobe
signals, and you can use it when DRAM is written to, read from, or
refreshed. Faster performance is gained in high speed, more stable
performance, in low speed.
This field is applied only when synchronous DRAM is installed in the
system.
Ø The Choice: Auto,2,3,4,5 or 6.
DRAM RAS# Precharge
If an insufficient number of cycles is allowed for the RAS to accumulate its
charge before DRAM refresh, the refresh may be-incompleted, and the
DRAM may fail to retain data. Fast gives faster performance; and Slow
gives more stable performance. This field is applied only when synchronous
DRAM is installed in the system.
Ø The Choice: Auto,2,3,4,5 or 6.
Precharge dealy (tRAS)
The precharge time is the number of cycles it takes for DRAM to accumulate
its charge before refresh.
Ø The Choice: Auto or 4~15.
System Memory Frequency
This item allows the user to adjust System Memory Frequency.
Ø The Choice: Auto,400MHz,533MHz or 667MHz.
System BIOS Cacheable
Selecting Enabled allows caching of the system BIOS ROM at
F0000h~FFFFFh, resulting in better system performance. However, if any
program is written to this memory area, a system error may result.
Ø The Choice: Enabled or Disabled.