M
M
X
X
4
4
6
6
S
S
O
O
n
n
l
l
i
i
n
n
e
e
M
M
a
a
n
n
u
u
a
a
l
l
P
P
B
B
S
S
R
R
A
A
M
M
(
(
P
P
i
i
p
p
e
e
l
l
i
i
n
n
e
e
d
d
B
B
u
u
r
r
s
s
t
t
S
S
R
R
A
A
M
M
)
)
For Socket 7 CPU, one burst data read requires four QWord (Quad-word, 4x16 = 64 bits). PBSRAM only needs one address decoding time
and automatically sends the remaining QWords to CPU according to a predefined sequence. Normally, it is 3-1-1-1, total 6 clocks, which is
faster than asynchronous SRAM. PBSRAM is often used on L2 (level 2) cache of Socket 7 CPU. Slot 1 and Socket 370 CPU do not need
PBSRAM.
P
P
C
C
-
-
1
1
0
0
0
0
D
D
I
I
M
M
M
M
SDRAM
DIMM that supports 100MHz CPU
FSB
bus clock.
P
P
C
C
-
-
1
1
3
3
3
3
D
D
I
I
M
M
M
M
SDRAM
DIMM that supports 133MHz CPU
FSB
bus clock.
P
P
C
C
-
-
1
1
6
6
0
0
0
0
o
o
r
r
P
P
C
C
-
-
2
2
1
1
0
0
0
0
D
D
D
D
R
R
D
D
R
R
A
A
M
M
Based on FSB frequency, the DDR DRAM has 200MHz and 266MHz two type of working frequency. Because of DDR DRAM data bus is
64-bit, it provides data transfer bandwidth up to 200x64/8=1600MB/s, and 266x64/8=2100MB/s. Hence, the PC-1600 DDR DRAM is
working with 100MHz and PC-2100 DDR DRAM is working with 133MHz FSB frequency.
P
P
C
C
I
I
(
(
P
P
e
e
r
r
i
i
p
p
h
h
e
e
r
r
a
a
l
l
C
C
o
o
m
m
p
p
o
o
n
n
e
e
n
n
t
t
I
I
n
n
t
t
e
e
r
r
f
f
a
a
c
c
e
e
)
)
B
B
u
u
s
s
Bus for the internal connection of peripheral devices, high-speed data channel between the computer and expansion card.
83
