Datasheet

Intel
®
Xeon
®
Processor C5500/C3500 Series
February 2010 Datasheet, Volume 1
Order Number: 323103-001 67
Interfaces
2.1.14.10 Rank Sharing
Throttling logic is shared when more than four ranks are present as described in the
following tables.
With 1 or 2 Single or Dual rank DIMMs on a channel, there are no more than four ranks
present. Each throttler is associated with a single rank. The logical ranks are not
consecutive due to the motherboard routing required to support three DIMMs on a
channel.
When more than four ranks are present, sharing is required. Adjacent logical ranks are
shared as they are on the same DIMM. Ranks on the same DIMM share the same DIMM
planar thermal mass. CKE sharing is across DIMMs. Since it is best to de-assert CKE
when throttling and CKE shared across DIMMs cannot be de-asserted until commands
stop going to ranks on both DIMMs, it is simpler to throttle all ranks at the same time
so that CKE may be de-asserted. Although CKE may be de-asserted on some ranks but
not others when there is no throttling, this lower command energy will not be captured.
When only one quad rank is present, CKE is shared due to DIMM connector limitations.
In this case, logical ranks 0, 1, 2, and 3 are present, but only Throttler 0 and 1 are
used.
2.1.14.11 Registers
Table 27 describes the parameters for this function. The size and association of each
parameter is described. If the parameter is per channel, there are three per socket. If
the parameter is per rank, there are 12 per socket. There is a limit of four throttlers per
rank as described in the preceding section.
Table 25. 1 or 2 Single/Dual Rank Throttling
Throttler Command Accumulation Which Logical Rank Throttled
0 accumulates the command power of rank 0 0
1 accumulates the command power of rank 4 4
2 accumulates the command power of rank 1 1
3 accumulates the command power of rank 5 5
Table 26. 1 or 2 Quad Rank or 3 Single/Dual Rank Throttling
Throttler Command Accumulation Which Logical Rank Throttled
0
If a read/write/act is issued to rank 0 or 1,
accumulate the read or write power.
else, if any rank has CKE asserted,
accumulate CKE asserted idle power
else accumulate CKE de-asserted idle power
all
1
If a read/write/act is issued to rank 2 or 3,
accumulate the read or write power.
else, if any rank has CKE asserted,
accumulate CKE asserted idle power
else accumulate CKE de-asserted idle power
all
2
If a read/write/act is issued to rank 4 or 5,
accumulate the read or write power.
else, if any rank has CKE asserted,
eccumulate CKE asserted idle power
else accumulate CKE de-asserted idle power
all
3
If a read/write/act is issued to rank 6 or 7,
accumulate the read or write power.
else, if any rank has CKE asserted,
accumulate CKE asserted idle power
else accumulate CKE de-asserted idle power
All