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Are dual processors better than single processors
Hi Folks,
What are the pros and cons of purchasing a dual versus single processor system?
Assuming that the dual processors are 2x4 core and the single processor is 1x8 core. Assuming they are equivalent in speed. For example is one more likely to overheat than the other?
speedstep
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August 19th, 2018 10:00
You throw out terminology that is not making sense. Only Xeon workstation class boards support 2 sockets aka Dual Processor. You can usually run these boards with only 1 processor and add another later on.
Cores are 1 2 3 4 6 8 etc. Hyperthreading makes the OS think there are more cores.
So QUAD core I7 looks like 8 cores when its actually 4.
Older Multi processor systems were 2 or 4 cores per cpu for XEON.
Which made for 4 or 8 cores with 1 or 2 sockets.
More Modern XEON chips can have 24 cores per socket.
Number of cores is not the determining factor as far as heating.
Its the TDP in watts.
Ancient Dual Core Processors used 130W PENTIUM D 965 (2 cores , 4 Threads) or even 150W. There are lots of differences Between Intel Pentium & Intel Core Processors
More Modern Core I7 chips with low power can use 65W max.
Mobile Units can get down to 25W because they run at very low clock speed.
Watts = Volts X AMPS so the way they have been lowering processor power is reducing the voltage on them. 5v is long gone for processor power. 3v or less is now the norm with 1.5v and lower being the new normal.
Even a really modern cpu like the Core I7 6700K uses only 91W.
Da_Vinman
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August 19th, 2018 21:00
All other things being equal (same Xeon family, die size, clock speed, etc.) then a single vs dual processor comparison you envision (each system = same number of cores, i.e. 2x2 vs 1x4 or 2x4 vs 1x8) would show the dual-CPU with slightly faster benchmark scores (proven under Xeon/other MP performance comparisons). This would be due to the dual multi-core processor systems having a separate memory channel for each processor, this doubling theoretical memory (and onboard GPU) bandwidth, but it is mitigated by the faster internal CPU-to-CPU bus of the single multi-core CPU.
As for the CPU heat question, obviously the single processor with the higher number of cores with a single heatsink-fan would create more of a cooling challenge than the dual-processors with two heatsink-fans.
The major con in a multi-processor system would obviously be cost, as both the CPUs and the platform would be more expensive (without a major increase in performance), and that's why single CPU multi-core is the most popular configuration for most systems. The only reason to do multi-CPU is if you absolutely require performance and scalability that goes beyond the levels of the fastest single CPU.