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Old 2015-08-05, 16:17   #1
fivemack
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Default 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?
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Old 2015-08-05, 17:27   #2
pinhodecarlos
 
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Quote:
Originally Posted by fivemack View Post
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 View Post
Looks like the final numbers are in. The Skylake 6700K beats a 4790K by 9% at stock speeds specifically on compute alone.
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Old 2015-08-06, 01:16   #3
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What is the maximum memory the chipset can address?
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Old 2015-08-06, 01:42   #4
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Quote:
Originally Posted by Xyzzy View Post
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.
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Old 2015-08-06, 05:17   #5
ATH
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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?
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Old 2015-08-06, 09:35   #6
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Quote:
Originally Posted by ATH View Post
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.
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Old 2015-08-08, 11:27   #7
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Quote:
Originally Posted by Xyzzy View Post
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
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Old 2015-08-08, 17:29   #8
ldesnogu
 
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Quote:
Originally Posted by fivemack View Post
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/
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Old 2015-08-09, 22:40   #9
Madpoo
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Quote:
Originally Posted by fivemack View Post
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
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Old 2015-08-10, 20:28   #10
pinhodecarlos
 
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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.
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Old 2015-08-18, 14:49   #11
ldesnogu
 
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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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