Disabling L2 Cache - Raspberry Pi User Manual

94
The voltage adjustment settings have upper and lower limits of 8 and -16, equivalent to 0 .2
V above stock voltage or 1 .4 V absolute and 0 .4 V below stock voltage or 0 .8 V absolute . The
voltage must be adjusted in whole numbers, and it cannot be adjusted below 0 .8 V (-16) or
above 1 .4 V (8 .)
The following settings are accessible from
As an example, the following lines entered into
boost of 0 .05 V to 1 .25 V and the memory chip a bigger boost of 0 .1 V to 1 .3 V:
over_voltage=2
over_voltage_sdram=4
As with other settings, deleting the lines from
return things to normal . Unlike the other settings in this section, however, the evidence will
remain in the form of a blown fuse in the BCM2835—rendering the Pi's warranty null and
void even after the default settings are restored .

Disabling L2 Cache

The Pi's BCM2835 SoC processor has 128 KB of Layer 2 cache memory onboard . Although this
memory is small, it's extremely fast . It's used to temporarily store—aka cache—data and instruc-
tions between the slower main memory and the processor itself to improve performance .
R A S P B E R R Y P I
❍ over_voltage—Adjusts the BCM2835's core voltage . Values are given as a whole
number (an integer) corresponding to 0 .025 V above or below the default value (
with a lower limit of
-16
❍ over_voltage_sdram—Adjusts the voltage given to the memory chip on the Pi . As
with
over_voltage
above or below the stock (
Additionally, you can adjust voltages for individual memory components using the fol-
lowing options:
•
over_voltage_sdram_c—Adjusts the voltage given to the memory controller .
Acceptable values are the same as with
•
over_voltage_sdram_i—Adjusts the voltage given to the memory's input/out-
put (I/O) system . Acceptable values are the same as with
•
over_voltage_sdram_p—Adjusts the voltage given to the memory's physical
layer (PHY) components . Acceptable values are the same as with
.
age_sdram
U S E R G U I D E
config.txt
and an upper limit of
, values are given as a whole number corresponding to 0 .025 V
,) with a lower limit of
0
over_voltage_sdram
config.txt
config.txt
:
.
8
and an upper limit of
-16
.
over_voltage_sdram
will give the BCM2835 a small
or deleting the file itself will
,)
0
.
8
.
over_volt-