Skylake S SiSoft Benchmark: Confusion and 30% IPC Improvement Over Haswell?[UPDATE]

[patrickjp93]

http://hwbot.org/newsflash/2764_skylake_and_broadwell_cpu_and_gpgpu_performance_figures_at_sisoft_sandra

 

We've come to expect Intel's S-series having clock rates in the mid-low 2GHz for base clock, but this benchmark smells very wrong based on what we currently know about Intel's architecture. The GPGPU label has 184 SP(stream processors), but Intel's Gen 8 graphics (Broadwell) architecture has 7 SIMD units per EU (same as Haswell and Gen 7.5), 8 EUs per subslice (2 fewer than Gen 7.5 to alleviate a data I/O bottleneck), and 3 subs per big slice (1 more than 7.5). Iris Pro 7200 will have 72 EUs reportedly, or 24 EUs per slice x 3 slices(if staying with the GT1,2,3/e modes) or 18 EUs per slice x 4 slices (rumored GT4 tier starting with Skylake for a while now). In neither case can you derive 184 SIMD units (Stream Processor is another word for a 32-bit SIMD unit). 24*7 = 168. Is it possible intel added an 8th SIMD unit? Well, no 24*8 = 192. Is it possible Intel took one off and it's 36 EUs per slice x 2 slices? 36x6 = 216. 

 

12 EUs per slice, 6 slices??? (really stretching it) Well no because 12 doesn't divide evenly into 184.

 

We're also not given the turbo clocks for either the CPU or GPU cores. If this is a low-power model, then this make some sense, but I still call BS because there are only so many ways to divide 72 into equal pieces, and in none of those configurations can you derive 184 SIMD units based on Intel's Macroarchitecture (the slices design).

 

Also, the DDR3 part, it's possible because Intel has said skylake will have both memory controllers, but that's disappointing if all we can see are the DDR3 pieces out in the wild, though when the DDR4 ones come out we can see if there actually is a performance difference between the two memory types for the iGPU.

 

Update: Possibly massive IPC increase

 

The hyperthreaded Haswell quad-core here (4770K) runs at 3.7 GHz with turbo boost and attains a score of 114.58 GFLOPs.

 

This Skylake quad-core presumably running at 2.3 GHz attains a score of 91.8 GFLOPs

Haswell's clock speed (3.7 GHz) divided by Skylake's (2.3 GHz) = 1.6087 times higher clock speed

Skylake's arithmetic score (91.8) multiplied by 1.6087 = 147.68 GFLOPs

147.68 GFLOPs (Skylake's theorized score at 3.7 GHz) divided by the equivalent Haswell score at the same clock speed (114.58) = 1.29x higher IPC, again based only on these assumptions of accuracy and scaling. I know SiSoft is far from a perfect source of specs and conditions, but for now it's all we have.

 

Also, the same calculations of the iGPU scores against the 4770k igpu suggests a 56% throughput increase per core assuming perfect scaling with the given 300MHz clock. We don't know the RAM speeds unfortunately.

[Darkman]

Probably DDR3 since most can't afford a $300 kit of 8GB RAM and about $200+ for an ok motherboard just because it supports DDR4.

[Fate]

Can I get an explain like I'm five? I don't understand most of what you just said.

[patrickjp93]

Probably DDR3 since most can't afford a $300 kit of 8GB RAM and about $200+ for an ok motherboard just because it supports DDR4.

DDR4 prices have fallen clean in half from where they started. They'll keep falling. Also, it's the S series. These are for people who'll build with 8GB of RAM tops.

[Guest]

Is there still chance that it will have ddr4 support?

[patrickjp93]

Can I get an explain like I'm five? I don't understand most of what you just said.

https://software.intel.com/en-us/file/compute-architecture-of-intel-processor-graphics-gen8pdf

 

You won't understand until you read that. It won't take you long.

[dizmo]

..ermm....cool...

[Fate]

https://software.intel.com/en-us/file/compute-architecture-of-intel-processor-graphics-gen8pdf

 

You won't understand until you read that. It won't take you long.

Thank you

[patrickjp93]

Is there still chance that it will have ddr4 support?

Intel has stated Skylake will support both memory controllers.

[patrickjp93]

..ermm....cool...

It is, because that means ES NDAs are going to start lifting for Broadwell desktop soon, but the premise of this makes no sense.

[Guest]

Intel has stated Skylake will support both memory controllers.

So There will be motherboards with ddr4 slots and those with ddr3 slots?

[patrickjp93]

So There will be motherboards with ddr4 slots and those with ddr3 slots?

Yes, and Intel also came out with a Unified DIMM adaptor to make DDR3 fit in DDR4 boards and vice versa. It's a mess...

[patrickjp93]

@LukaP, I don't think I've forgotten how to do basic math. Can you make 184 Stream Processors make sense in all this given what we know of Intel's graphics architecture?

[brownninja97]

honestly i dont care, ddr4 offers better performance but its not like it will be worth the price any time soon

[patrickjp93]

honestly i dont care, ddr4 offers better performance but its not like it will be worth the price any time soon

In 6 months? Ah I think you're full of it. DDR3 prices started rising right after black friday, and DDR4 has tumbled by 46% since it launched except at the highest end.

[brownninja97]

In 6 months? Ah I think you're full of it. DDR3 prices started rising right after black friday, and DDR4 has tumbled by 46% since it launched except at the highest end.

in reality its just me wanting to not have to get more ram if and when i upgrade.

[patrickjp93]

I hope it doesn't work with springs

I may or may not have an NDA in effect which requires I not "discuss concretely the designs, features, and quality of current Intel products as internally specified."

[patrickjp93]

Then I'll throw JIC

Little springs (for example 2 mm) = broken things

What is a spring without being a spring?

[patrickjp93]

L8 here, not thinking a lot... some compressible and flexible polymer ?

Think tortion not sompression.

[Techhog]

I thought is was well known that Skylake supports both DDR3 and DDR4 (though not on the same board).

[patrickjp93]

Like on alarm clocks -.-?

More stupidly complicated.

[totjup5]

I like the ddr3, that means I wouldn't have to swap out my 16GB of ddr3 1866 just yet. And considering I've had no performance problems with it I really don't think ddr4 is necessary for me yet.

[patrickjp93]

I like the ddr3, that means I wouldn't have to swap out my 16GB of ddr3 1866 just yet. And considering I've had no performance problems with it I really don't think ddr4 is necessary for me yet.

It's going to mean a round of bad motherboards for certain, just as it was in the transitional year between DDR2&3. What a mess. Leave it to Intel to not know how to make a clean break. At least AMD did between DDR2&3. Instant switch, even though it was later than Intel.

 

Now if AMD can just nix the north bridge memory controller being off the CPU... Have they done that on their FM platform? I know they haven't touched the AM platform since the release of Bulldozer, but still...

[Glenwing]

It's going to mean a round of bad motherboards for certain, just as it was in the transitional year between DDR2&3. What a mess. Leave it to Intel to not know how to make a clean break. At least AMD did between DDR2&3. Instant switch, even though it was later than Intel.

 

Now if AMD can just nix the north bridge memory controller being off the CPU... Have they done that on their FM platform? I know they haven't touched the AM platform since the release of Bulldozer, but still...

The FM platform does have an integrated Northbridge.

Also I thought there was a generation of of Phenom II parts that had both DDR2 and DDR3 controllers?

[Opcode]

It's going to mean a round of bad motherboards for certain, just as it was in the transitional year between DDR2&3. What a mess. Leave it to Intel to not know how to make a clean break. At least AMD did between DDR2&3. Instant switch, even though it was later than Intel.

 

Now if AMD can just nix the north bridge memory controller being off the CPU... Have they done that on their FM platform? I know they haven't touched the AM platform since the release of Bulldozer, but still...

DDR4 isn't exactly all that consumer friendly yet (price/performance) and probably wont be for some time to come. It's a wise choice to stick to supporting DDR3 in order to not break consumer banks. Sales would more than likely fall off for Skylake otherwise. Who really wants to dump $200+ into new ram. FM2 has the north bridge controller completely integrated. Carrizo integrated the south bridge controller as well. FM2r2 chips have supported DDR3 and DDR4 for some time now. Tho AMD seems to not want to transition to DDR4 as it's still not cost effective for the consumer.