Oracle 9i R2 and Hyper threading

Hi
This is a matter of confusion to me, I've tested Oracle 9.2.0.1.0 on several machines with Hyper threading 1 CPU Intel and Dual Xeon servers.
When installing oracle the CPU_COUNT and PARALLEL_THREAD_PER_CPU parameters are set automatically.
ie: Intel 3.0 HT
CPU_COUNT = 2
PARALLEL_THREAD_PER_CPU = 2
Dual Xeon 2.8 HT
CPU_COUNT = 2
PARALLEL_THREAD_PER_CPU = 4
with this default settings our application is dragging it's feet (developped on 4.5 upgraded to 6i client/server)
But if we set
CPU_COUNT = 1
PARALLEL_THREAD_PER_CPU = 2
for the Intel the app goes lightspeed
and
CPU_COUNT = 1
PARALLEL_THREAD_PER_CPU = 1
for the xeon again lightspeed
I didn't face this problem with non HyperThreasding CPUs
My question:
Why is this anomoly, what's the workaround without changing the CPU_COUT parameter?
did anybody else face any problem like this? does this happen in 10g???
Thanks in Advance
Tony S. Garabedian

Any suggestions? Any ideas??

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A recommendation does not mean the absolute best solution for every situation. There has been no information about any particular software deployment or even the particular CPU in question.
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Does disable CPU hyper threading will have direct impact or maybe unexpected behavior to Oracle RAC database?
Actually the background of this question is we have many received packet queuing on the network layer waiting to be processed. Investigation leads to the processor utilization which shows that many processor are still in idle state or not used when the other processors are busy processing incoming request.
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CPU Count Consideration for Oracle Parameter Setting When Using Hyper-Threading Technology (Doc ID 289870.1)
Oracle and Hyper-Threading (Doc ID 205089.1)
Using PROCESSOR_GROUP_NAME to bind a database instance to CPUs or NUMA nodes (Doc ID 1585184.1)
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Oracle 9i R2 and Hyper threading

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