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Hi Intel Experts:
I cannot find the latest Intel Haswell CPU GFlops, could you please let me know that?
I want to understand the performance difference between Haswell and Ivy-bridge, for example, i7-4700HQ and i7-3630QM. From Intel website, I could know i7-3630QM's GFlops is 76.8 (Base). Could you please let me know that of i7-4700HQ?
I get some information from internet that:
Intel SandyBridge and Ivy-Bridge have the following floating-point performance: 16-SP FLOPS/cycle --> 8-wide AVX addition and 8-wide AVX multiplication.
Intel Haswell have the following floating-point performance: 32-SP FLOPS/cycle --> two 8-wide FMA (fused multiply-add) instructions
I have two questions here:
1. Take i7-3632QM as an example: 16 (SP FLOPS/cycle) X 4 (Quad-core) X 2.4G (Clock) = 153.6 GFLOPS = 76.8 X 2. Does it mean that one operation is a combined addition and multiplication operation?
2. Does Haswell have TWO FMA?
Thank you very much for any comments.
Best Regards,
Sun Cao
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Hi Sergey:
You can find CPU GFlops at: http://www.intel.com/support/processors/sb/CS-017346.htm
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Hi Sergey:
I do not have Haswell systems now.
Even I have it, it will be very helpful if Intel could provide me more information.
Best Regards,
Sun Cao
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Haswell execution engine has two Ports dedicated also to FMA(one FMA per port) instructions(Port0 and Port1) so you have doubled bandwidth of gflops/cycle.
On Haswell one FMA operation combines multiplication and addidtion when compared to previous architecture such a operation could stall two ports when executing at the same time.
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>>>By the way, two numbers I gave you are for Pentium 4 and you can see that i7-3630QM is ~42x faster when processing is done using all cores.>>>
Are those results obtained from testing Vec_samples?
Afaik Pentium 4 cannot calculate at the same time fadd and fmul.Haswell core is able to schedule for execution one FMA(two fp instructions) per one thread it is a tremendous improvement in raw processing power when compared to Pentium 4
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Thanks
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Actually on Ivy Bridge you have 1 wide fadd/cycle and 1 wide fmul/cycle it can be either SP(8 flops) or DP(4 flops) and mulitplied by 4 cores and by clock grequency 2.4 ghz = 76.8 Gflops.
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Hi Sergey:
You can find CPU GFlops at: http://www.intel.com/support/processors/sb/CS-017346.htm
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>>>As you can see my number is ~21% lower that Intel's number and this is because our test cases are different. I don't think we will know how 76.8 number was measured unless Intel releases source codes, or informs everybody that some Open Source test was used.>>>
It could be theoretical peak performance bandwidth.Real application can affect this result by introducing memory stalls or instruction interdependencies.
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Speed for Haswell running at 4GHz here is ~116GFlops in Intel optimized linpack from MKL.
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>>...Speed for Haswell running at 4GHz here is ~116GFlops in Intel optimized linpack from MKL..>>>
Haswell can pose a challenge for low end GPUs in terms of DP Gflops.
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