Hello,
I am thinking of buying a used HP D800 workstation with dual Xeons for some (multithreaded/parallel) scientific simulations. So I am looking at your scores trying to guess as confidently as possible the performance I can be expecting from it. Looking at your Multiple-CPU scores and the corresponding same, single CPU scores, I am in generally seeing that adding a second identical CPU to the mix does not not double the score, but rather suggests a much lower gain.
For example a [Dual CPU] Intel Xeon E5-2697 v3 @ 2.60GHz currently scores 30106, while this processor scores 22143 on its own, that's a 1.36 performance gain for the dual CPU. Or, looking at the processor I am actually looking at, the [Dual CPU] Intel Xeon X5650 @ 2.67GHz, it scores 11675, while the same single CPU scores 7599, so 1.53 speed up.
So one question is: Are the scores in the two charts (single CPU and Multiple CPU) directly comparable? Adding a second (very expensive!) CPU and getting a mere 36% gain from it just doesn't sound great somehow.
Another more general question is this: Suppose we have a multithreaded application whose performance scales linerly up to 8 cores/threads with a constant say 75% parallel efficiency. So using 4 cores should give a 3x speed up over a single core, using 8 cores should make it 6 times faster. Now let's say we have an 8-core and two quad-cores, their cores having identical single-threaded performance. Would the 8-core chip always significantly overperform a dual CPU made up from the two quad-cores for the supposed application? (because of memory latency issues I understand). Or put another way, when trying to guess my possible gain in multithreaded simulation performance over my current i7-920 (scoring around 5000), should I be roughly comparing to 11675 (the dual Xeon score), or closer to the double of each of those Xeons, i.e. 15200?
For all that let's suppose that other factors, like memory speed/bandwidth don't favour one or the other.
Thanks
I am thinking of buying a used HP D800 workstation with dual Xeons for some (multithreaded/parallel) scientific simulations. So I am looking at your scores trying to guess as confidently as possible the performance I can be expecting from it. Looking at your Multiple-CPU scores and the corresponding same, single CPU scores, I am in generally seeing that adding a second identical CPU to the mix does not not double the score, but rather suggests a much lower gain.
For example a [Dual CPU] Intel Xeon E5-2697 v3 @ 2.60GHz currently scores 30106, while this processor scores 22143 on its own, that's a 1.36 performance gain for the dual CPU. Or, looking at the processor I am actually looking at, the [Dual CPU] Intel Xeon X5650 @ 2.67GHz, it scores 11675, while the same single CPU scores 7599, so 1.53 speed up.
So one question is: Are the scores in the two charts (single CPU and Multiple CPU) directly comparable? Adding a second (very expensive!) CPU and getting a mere 36% gain from it just doesn't sound great somehow.
Another more general question is this: Suppose we have a multithreaded application whose performance scales linerly up to 8 cores/threads with a constant say 75% parallel efficiency. So using 4 cores should give a 3x speed up over a single core, using 8 cores should make it 6 times faster. Now let's say we have an 8-core and two quad-cores, their cores having identical single-threaded performance. Would the 8-core chip always significantly overperform a dual CPU made up from the two quad-cores for the supposed application? (because of memory latency issues I understand). Or put another way, when trying to guess my possible gain in multithreaded simulation performance over my current i7-920 (scoring around 5000), should I be roughly comparing to 11675 (the dual Xeon score), or closer to the double of each of those Xeons, i.e. 15200?
For all that let's suppose that other factors, like memory speed/bandwidth don't favour one or the other.
Thanks
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