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 2015-08-05, 16:17 #1 fivemack (loop (#_fork))     Feb 2006 Cambridge, England 11000110100012 Posts So does skylake-nonXeon actually get us anything? Sky Lake has launched, were I to go mad this moment I could get a system shipped to me by Friday. 4GHz turbo to 4.2GHz, two channels of DDR4 memory support, reasonably fancy GPU for which Windows 10 might have useful OpenCL drivers. No new instructions. No CrystalWell L4 cache. Not the slightest information provided about improvements to the execution pipeline. Is this likely to have any advantage over i7-4790K?
2015-08-05, 17:27   #2
pinhodecarlos

"Carlos Pinho"
Oct 2011
Milton Keynes, UK

41×113 Posts

Quote:
 Originally Posted by fivemack Sky Lake has launched, were I to go mad this moment I could get a system shipped to me by Friday. 4GHz turbo to 4.2GHz, two channels of DDR4 memory support, reasonably fancy GPU for which Windows 10 might have useful OpenCL drivers. No new instructions. No CrystalWell L4 cache. Not the slightest information provided about improvements to the execution pipeline. Is this likely to have any advantage over i7-4790K?
Please ship one for me too.

Quote:
 Originally Posted by John P. Myers Looks like the final numbers are in. The Skylake 6700K beats a 4790K by 9% at stock speeds specifically on compute alone.

 2015-08-06, 01:16 #3 Xyzzy     "Mike" Aug 2002 71·107 Posts What is the maximum memory the chipset can address?
2015-08-06, 01:42   #4
Mark Rose

"/X\(‘-‘)/X\"
Jan 2013
Ͳօɾօղէօ

28·11 Posts

Quote:
 Originally Posted by Xyzzy What is the maximum memory the chipset can address?
As best as I can tell, it's limited to 64 GB. 32GB modules are coming on to the market, and I haven't found anything regarding whether the 64 GB limit is hardware or simply a lack of testing with larger modules.

 2015-08-06, 05:17 #5 ATH Einyen     Dec 2003 Denmark 1011010010102 Posts Unfortunately Skylake has "only" dual channel DDR4, so I guess Haswell-E with quad-channel DDR4 are still going to be faster for LL test? Anyone tested the difference between dual- and quad channel memory for LL tests?
2015-08-06, 09:35   #6
VictordeHolland

"Victor de Hollander"
Aug 2011
the Netherlands

100100110002 Posts

Quote:
 Originally Posted by ATH Unfortunately Skylake has "only" dual channel DDR4, so I guess Haswell-E with quad-channel DDR4 are still going to be faster for LL test? Anyone tested the difference between dual- and quad channel memory for LL tests?
My i7 3770 can easily saturate dual channel DDR3-2133. Fast DDR4 memory will help, but I'm afraid you'll also run into memory bandwidth bottlenecks with Skylake.
In the end it is all about price/performance and on that front Skylake will probably win it over the more expensive Haswell-E.

2015-08-08, 11:27   #7
ldesnogu

Jan 2008
France

24×3×11 Posts

Quote:
 Originally Posted by Xyzzy What is the maximum memory the chipset can address?
It seems to be 32GB: http://ark.intel.com/products/88195/...up-to-4_20-GHz

2015-08-08, 17:29   #8
ldesnogu

Jan 2008
France

21016 Posts

Quote:
 Originally Posted by fivemack No new instructions.
Compared to Haswell there's ADX. That should be useful for MP computations.

Quote:
 Not the slightest information provided about improvements to the execution pipeline. Is this likely to have any advantage over i7-4790K?
Some hints here: FMA latency reduced by 1. VADD latency increased but throughput increased.

More data: http://instlatx64.atw.hu/

2015-08-09, 22:40   #9
Serpentine Vermin Jar

Jul 2014

3·1,091 Posts

Quote:
 Originally Posted by fivemack Sky Lake has launched, were I to go mad this moment I could get a system shipped to me by Friday. 4GHz turbo to 4.2GHz, two channels of DDR4 memory support, reasonably fancy GPU for which Windows 10 might have useful OpenCL drivers. No new instructions. No CrystalWell L4 cache. Not the slightest information provided about improvements to the execution pipeline. Is this likely to have any advantage over i7-4790K?
In case anyone cares, I dug through and found just this one GIMPS benchmark for a Skylake system. I guess we need more people with Skylakes to run benchmarks and check them in:
i5-6440HQ @ 2.9 GHz

It's just an i5-6440HQ @ 2.6 GHz, so compare accordingly (it was running at 2.9 GHz for the benchmark, probably stock turbo speed).

I was trying to find a comparable i5-5xxx at a similar clock speed... maybe this one:
i5-5257U @ 3 GHz

Then there's this... it's a Haswell clocked faster (3.3 GHz) and it seemed to have similar timings to Skylake at the 2.9 GHz clock. Pretty cool:
i5-5675C @ 3.3 GHz

 2015-08-10, 20:28 #10 pinhodecarlos     "Carlos Pinho" Oct 2011 Milton Keynes, UK 41·113 Posts One of the things it's concerning me is the TDP of Broadwell vs Skylake and therefore the specific consumption analysis of both processors simulating/crunching/testing the same amount of work.
 2015-08-18, 14:49 #11 ldesnogu     Jan 2008 France 24×3×11 Posts GMP is getting nice speedups for Skylake over Haswell: https://gmplib.org/gmpbench.html Code:  base app GMP Score CPU freq mult div gcd gcd rsa pi bench /GHz Core i5-6600 (Skylake 6MB L3) 3500 68173 63168 10973 7417 9030 62.7 5049 1443 2015-08-17 Core i7-4790 (Haswell 8MB L3) 4000 66464 59923 11336 7487 8294 62.0 4882 1220 Xeon E5-1650v2 (Ivy Bridge 12MB L3) 3500 52036 49885 9108 5946 6756 50.7 3956 1130 2015-04-30 Core i5 2500 (Sandy Bridge 6MB L3) 3300 44474 43235 7960 5265 5827 44.0 3425 1038 2015-05-01 Phenom 1090T (K10 6MB L3) 3200 42183 40877 6751 4579 5876 42.4 3257 1018 2015-05-26 Core i3 5010U (Broadwell 3MB L3) 2100 37245 35997 6179 4199 4973 35.9 2831 1348 2015-05-14 Nice but not enough to upgrade from Haswell based on that only ;)

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