SMP 166 MHz Processor Card
Up to six processor cards can be installed onto the multiprocessor
bus on the Server 720. Each processor card has the following functions:
- Intel Pentium processor. Currently
announced are 100, 133, and 166 MHz options.
- 512 KB of write-back L2 cache
- 192 byte of L3 (victim) cache
- Bus interface and control logic
Processor card types:
- 100 MHz (P/N 94G2724) - For all OS other than NW 4.1 SMP
- 100 MHz (P/N 94G6054) - For NetWare 4.1 SMP only
- 133 MHz (P/N 94G6055) - For all OS other than NW 4.1 SMP
- 133 MHz (P/N 94G6056) - For NetWare 4.1 SMP only
Note: Of a maximum of six processors in the 720,
the number of earlier 166 MHz standard processor boards is limited to two. This
only applies to processor boards delivered as standard processors. This limit
of two 166 MHz standard processors is due to a limitation of the power supply.
These 166 MHz boards draw current from the 5 V power supply and not the 3.3 V
supply as do the other processor boards. All 166 MHz optional processors boards
(P/N 94G6057) are 3.3 V. They may be added without a restriction.
SMP 166 MHz Processor Card FRU P/N 76H3545 (or 76H3248?), P/N 94G6057(R)
J2-5 test header pads?
P1 2x10-pin header pads
P2 JTAG connector pads
U1,2 Corollary DPX 94C101B
U3 Corollary CBC 94C102B
U4 MCM62995AFN15 16Kx16 SRAM (TAG?)
U6-9 64Kx16 SRAM (L2 cache)
U14 66.6667? MHz osc
? 3x5-pin jumper block
U6-9 MCM67C618FN9 or IBM 041813PPL-12 64G2525 64Kx16 SRAM (L2 cache)
Note: Some component types and reference
designators were taken from processor cards other than the SMP 166 MHz variant.
More data and verification needed!
Important: Please understand Where/what is the
difference between FRU - OPT - MKT P/Ns
||Server 720 200Mhz Processor Option II
||Server 720 SMP 100Mhz Processor Option II
||Server 720 SMP 100Mhz Proc
||Server 720 SMP 133Mhz Processor Option
||Server 720 SMP 133Mhz Processor Option II
||Server 720 SMP 133Mhz Processor Option II
||Server 720 SMP 166Mhz Processor Option II
||Server 720 SMP 166Mhz Proc
Server 720 SMP 133MHz Processor Opt. II (RETAIN: #H132301)
Important Information if you have installed the IBM PC Server 720 SMP Option II.
OBI Processor Card P/N
94G6054 PC Server 720 SMP 100MHz Proc. Option II
94G6056 PC Server 720 SMP 133MHz Proc. Option II
94G6057 PC Server 720 SMP 166MHz Proc. Option II
The above Options are only supported with 'Novell NetWare V-3.12 V-4.1' or
SMP operating system.
The origin 100MHz processor card (or cards) installed in the server must be
removed before installing a server option. If you are not sure if one or more
of the processor cards inside the server are one of the original 100MHz
processor cards, do the following:
- Remove a processor card from the server and locate the FRU P/N printed on a
label on the card.
- If the FRU P/N is 71G0692, the processor card is not compatible with the
new processor option and must be removed before installing the new processor
option. see Note 1.)
- If the FRU P/N is not 71G0692, reinstall the processor card.
- Repeat steps 1 and 2 with all of the other processor cards currently in the
Once you have completed steps 1 through 4 for all of the processor cards
currently installed in the server, then you can install the new processor
Note 1.) The processor card 76H6852 (71G0692)
should be exchanged with FRU P/N 76H6850 (75H9648) if NetWare SMP is installed.
Do not replace the card if OS/2 or any other Operating System is installed,
because this processor card FRU P/N 76H6850 (75H9684) is designed to work with
NetWare SMP only!
System Unit (PC Server 720 - Type 8642)
Micro Channel Models OZO, 1Z0, 2ZS, 4ZS
P54C-100/66MHz Processor Card 76H6852
P54C-133MHz Processor Card 75H9688
P54C-133MHz Processor Card 75H9686
P54C-166MHz Processor Card
(Model 0EN, 0E1, 2E1) (75H9690)
(all six jumpers are default set to NORM
right side - outer position) 76H3545
P54C-200MHz Processor Card 76H7147
SMP 200MHz Processor Upgrade Opt-II 76H2572
(Any combination 100-200MHz up to 6
If the performance has degraded on the PC Server 720 with more than one
processor, or if the operating system does not detect all of the processors,
then one or more processors may be failing.
- Multiprocessor Error IP: 1xxDSxx or FP: 1xxDSxx on LCD panel.
- Test Error EP: 106S appears on the LCD panel.
- Error 0095xxxx appears on the display or the LCD panel.
Note: A Test Error EP: 106S, or Multiprocessor
Error IP: 1xxDSxx or FP: 1xxDSxx, where (S) is the slot number of the processor
card, indicates the slot number of the failing processor card or indicates the
slot number of a good processor card that is reporting the error caused by the
failing processor card.
Follow this procedure to isolate the failing processor:
- Power off the system and connect an ASCII terminal or laptop to the serial
port. Use the serial port on the Server 720 which connects to the internal
ribbon cable labeled P2.
- Reboot using the System Diagnostic Diskette.
- Select option 3: Extended ROM Resident Diagnostics.
- Note the slot number of the failing processor.
- Replace the failing processor and rerun the diagnostics.
Refer to the IBM PC Server HMM, publication number S30H-2501-01, page 377,
for additional information on error codes.
The PC Server 720 Extended ROM Resident Diagnostics can isolate a failing
processor card in any of the six(6) processor slots.
To ensure highest performance, the processor and cache are designed to
operate with zero wait states. In addition, all processor cards are fully
symmetrical for main memory access, I/O, and interrupts. This means that no
single processor can be a bottleneck, for example, through having to process
all the hardware interrupts in the system.
In an SMP system, some data might be held within multiple processor caches.
If this data is modified by one processor, then it needs to be updated in the
other caches before another processor operates on out-of-date information. This
is called cache coherency and is handled by the MESI (Modified, Exclusive,
Shared or Invalid) protocol.
Each of the PC Server 720 processor cards has three levels of private cache.
Lower level caches are typically very fast but also very expensive. In general,
the closer to the processor, the faster and more expensive the cache will
The first, or L1 cache, is built into the Pentium processor. This is th
first place the processor will look when it needs its next instruction or piece
of data to operate on. If this data is not contained in L1, the system next
searches the second level, or L2 cache. If the information is found in either
of these locations, the processor can continue without incurring wait states.
However, if the information is still not available from the L1 cache or the L2
cache, the processor will need to obtain it from main memory. Depending on the
speed of the memory subsystem, it may take a few clock cycles for this
transaction to complete.
When the information is retrieved from main memory, it is stored in a free
cache location. If there are no free locations, then the new data replaces the
least frequently used information currently stored in the cache.
Since the Server 720 uses performance-boosting write-back cache, this least
frequently used data may have already been modified by the CPU and must,
therefore be evicted first or written back to memory. In most systems, the
processor would have to wait for that data to be written out before it could
bring in a new line of cache.
The Server 720 takes the unique approach of adding a small six-line L3 cache
to each processor card. The 720's L3 or victim cache allows that data to be
quickly cleared from L2 to L3 making room for new information and allowing
modified data to be written to main memory later during free bus cycles. In
addition, this information is still available to be quickly accessed if needed
in future cycles.
This approach improves the overall cache hit ratio with little additional
cost while saving significant clock cycles during the write back or eviction
process. Access to data in any of these three caches can be accomplished with
zero wait states so the processor continues work on its applications without
It may seem more effective to simply make the L2 cache much larger to
increase the cache-hit ratio directly. However, since the cache memory tends to
be expensive, the size of the L2 cache is carefully chosen to provide a high
cache-hit rate at reasonable cost. As it takes time to search the cache for the
required information, it is also possible to have a cache that is too large and
too slow to respond to each request.
The carefully balanced cache design of the 720, however, provides for a high
percentage of zero-wait states processing resulting in excellent multiprocessor