AMD Carrizo Pre-release thread

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cbn

Lifer
Mar 27, 2009
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All of the 15h parts are limited to 2400MHz max. by the design. The "new" memory controller introduced in Steamroller is the worst piece of hack job I´ve ever seen. It is some off-the-shelf solution "integrated" (whisky tangoed) to the design by using some duct tape and hot snot. It´s functionality relies fully on vast amount of C code (AGESA).

The memory controller in Excavator designs is basically the same thing, the only major difference being the memory types it supports (DDR3/GDDR5 combo vs. DDR3/DDR4 combo).

The "quality" of the memory controller matches pretty closely the rest of the Steamroller design: nothing works (together). Steamroller is like the last ditch design with all of the scrap thrown into a same can and slightly stirred. Each of the different parts work well separately, but when combined together the outcome is just absolute junk. Normally this type of bugs and errata can be found in early evaluation silicon, not in something that gets released to the market.

I certainly hope (pray) that anyone who worked on Steamroller have had nothing to with the upcoming 17h family (or any other AMD product for that matter) :'(

So perhaps another reason GDDR5 was included was because the DDR3 was so bad?

And AMD crossed their fingers one day they could use it.

Reason: it seems very mysterious to me AMD would include the option for GDDR5 as system RAM for an APU with only 512sp. This, unless, there was something wrong with the DDR3.
 
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Abwx

Lifer
Apr 2, 2011
11,543
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Those prices are a little hard to swallow. $644 for a 14" one module A4-5150M??? I got a 13" Dell with Core i5 6200U for $499. Why would anyone get those HP laptops?

What are you talking about, you linked an outdated page with an old serie of Probooks using Richland APUs....

Probooks are low cost laptops, here the current pricing with Carrizo-L :

https://geizhals.de/hp-probook-455-g3-p4p61ea-abd-a1350184.html?hloc=at&hloc=de

So the Carrizo ones will be about 50-150€ more expensive..
 

NTMBK

Lifer
Nov 14, 2011
10,322
5,352
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So perhaps another reason GDDR5 was included was because the DDR3 was so bad?

And AMD crossed their fingers one day they could use it.

Reason: it seems very mysterious to me AMD would include the option for GDDR5 as system RAM for an APU with only 512sp. This, unless, there was something wrong with the DDR3.

The HD7750 is a 512 shader GPU, and it needs GDDR5 to run at full performance. http://ht4u.net/reviews/2012/msi_ra...39.php&usg=ALkJrhi1G4TxkhzXnvN1ZfRJ3KdXukbpQQ That was only with DDR3-1600, much slower than Kaveri supports, but it also didn't have to share it with a CPU.
 

cbn

Lifer
Mar 27, 2009
12,968
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The HD7750 is a 512 shader GPU, and it needs GDDR5 to run at full performance. http://ht4u.net/reviews/2012/msi_ra...39.php&usg=ALkJrhi1G4TxkhzXnvN1ZfRJ3KdXukbpQQ That was only with DDR3-1600, much slower than Kaveri supports, but it also didn't have to share it with a CPU.

Oh yes, I did know about the GPU.

I was actually thinking about how the two memory controllers (GDDR5 and DDR3) affected the CPU.

Reason is that with either 4GB or 8GB GDDR5 as system RAM the iGPU only uses a small part of that. The rest of the GDDR5 memory is used by the CPU.

So if the GDDR5 memory controller was a significantly better design than the DDR3 controller I wonder if there were some gains beyond those expected with the iGPU.

With that noted, I did notice the Stilt write the following after that post here and here.

Do you have any estimates on how much performance Steamroller have lost due to this?

If we expect that a proper & properly implemented memory controller would reach similar frequencies (2666MHz+) that Intel IMCs do, then the performance penalty for the high-end Steamroller APUs in 3D is around 15%.

The core µarch is what it is and a proper memory controller would not make it any better in general. There are some cases where a proper IMC would improve the performance quite significantly (e.g data de/compression, SuperPI) which is latency & bandwidth critical. The memory latency on Steamroller is over 30% higher than on the previous generation at the same settings (MEMCLK and timings).


Excavators (CZ, BR) use almost identical memory controller IP as Steamroller does. The only difference is that Excavator has DDR4 Phy in place of GDDR5 Phy found in Steamroller. The DDR3 Phy is identical.

It is bat*hit crazy that the new memory controller has that much HIGHER latency. At 2133MHz CL12-12-12-2T (3400MHz CPU, 1200MHz NCLK) AIDA64 (5.60.3755) measures 112.4ns latency for the DRAM on Carrizo. Richland running with identical settings (excl. 1500MHz NCLK) gets 70.8ns.

Steamroller, which was the first design to implement the completely new memory controller has over 30% higher latency than Piledriver based Richland. For some reason the latency has increased even further in Excavator. While AIDA64 isn´t exactly the optimal method to measure the DRAM latency, based on real world applications (e.g. LZMA, RAR de/compression) it is clear that the memory latency is infact significantly higher than on the older memory controller. Quite an achievement, since the old memory controller was introduced in K8. Until it´s decommissioning it received only minor upgrades.
 
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zir_blazer

Golden Member
Jun 6, 2013
1,192
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Could it be possible that the reason why the Steamroller and Excavators IMCs latency is higher than previous generations is because they're IGP-first and throughput optimized? After all, GDDR5 supposedly achieve much higher bandwidth than standard DDR3 at the cost of higher latency, and Steamroller was going to support GDDR5. It makes some sense.
 

desura

Diamond Member
Mar 22, 2013
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So from the anandtech article, it looks like Carrizo is going to fall into the same mediocrity that previous AMD releases fell into.

AMD needs to create a Surface to showcase their designs. I want to like AMD, but just trying to find an A10 laptop is hard, and they're overpriced even then.
 

desura

Diamond Member
Mar 22, 2013
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Also, anyone remember when Apple considered the AMD processors for the macbook air? Any chance this could ever happen again? All AMD needs to do to get back in the game is to cut Apple a sweetheart deal.
 

monstercameron

Diamond Member
Feb 12, 2013
3,818
1
0
Could it be possible that the reason why the Steamroller and Excavators IMCs latency is higher than previous generations is because they're IGP-first and throughput optimized? After all, GDDR5 supposedly achieve much higher bandwidth than standard DDR3 at the cost of higher latency, and Steamroller was going to support GDDR5. It makes some sense.
It's gotta be related to how they implemented some of the hsa technologies.
 

ShintaiDK

Lifer
Apr 22, 2012
20,378
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Also, anyone remember when Apple considered the AMD processors for the macbook air? Any chance this could ever happen again? All AMD needs to do to get back in the game is to cut Apple a sweetheart deal.

I think that was a rumour only.
 

el etro

Golden Member
Jul 21, 2013
1,581
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Also, anyone remember when Apple considered the AMD processors for the macbook air? Any chance this could ever happen again? All AMD needs to do to get back in the game is to cut Apple a sweetheart deal.

Was real at Llano era, reappeared again as a rumor with Raven Ridge(zen APU).
 

el etro

Golden Member
Jul 21, 2013
1,581
14
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Raven Ridge is more like a hope, as there is no such product yet.

A hope? WAT?

Is real, just don't exist on official public roadmaps. Unlikely as a hope is that Raven Ridge will have integrated HBM.
RR is Time-framed to 1H2017, probably being the second Zen product after the new FXs. Zen CPU and Polaris GPU.
 

ShintaiDK

Lifer
Apr 22, 2012
20,378
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Q3 2017 D:

And most definitely no HBM around even at that point :'(

I dont get why they never did a ESRAM/EDRAM cache. They developed it for MS.

HBM on an APU is pretty much a fantasy until it can replace system memory completely at a low cost.
 

The Stilt

Golden Member
Dec 5, 2015
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eDRAM would increase the cost so heavily that there would be very little demand for a expensive and utterly unbalanced part like that. The iGPU would be a complete monster, however the CPU cores would still be lacking heavily.

The trouble with AMDs APU concept is that these things do everything, but nothing particularly well. While AMD obviously could not fix the Bulldozer µarch over night, there are several other things which could have been easily fixed.

Let´s use Carrizo as an example:

- AMD knew about the severe limitations of the new memory controller to be used in Carrizo / Bristol Ridge already before the launch of Kaveri. There were several suitable DDR4-3200MHz capable IPs available, but AMD chose to keep the one which could not do higher than 2400MHz. At the same time the performance of their iGPUs (at the time, superior) have been completely bottle necked by the memory bandwidth since the release of the very first APU (Llano).

- UVD6 implementation: A) It was know already back in 2012 that UltraHD Blu-ray will use HEVC, with 10-bit color depth to be precise. Despite that AMD choose to implement only 8-bit support in Carrizo.

- UVD6 implementation: B) Lack of VP9 hardware decoding. Google has and does offer VP9 hardware decode & encode IPs free of charge. Still, AMD chose not to include VP9 support in their UVD decoder block in Carrizo. Inability to decode VP9 on hardware is a major issue for this type of product, since the most popular video service on planet (Youtube) uses HTML5 by default. Carrizo users must specifically force Youtube back to Flash based interface for the hardware decoding to work. Using the CPU to decode high resolution videos in some cases is not even possible and never power efficient.
 

The Stilt

Golden Member
Dec 5, 2015
1,709
3,057
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Do you have a source? Or good feeling about that prediction?

Just common sense. If you look up few facts about HBM2 you can see why it´s extremely unlikely that it will be implemented in a mainstream product like APU (cost, complexity, physical size, capacity). HPC / Custom APUs are a completely different topic, obviously.
 
Aug 11, 2008
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A hope? WAT?

Is real, just don't exist on official public roadmaps. Unlikely as a hope is that Raven Ridge will have integrated HBM.
RR is Time-framed to 1H2017, probably being the second Zen product after the new FXs. Zen CPU and Polaris GPU.

Obviously what i meant was, we have no idea what the performance will be. We dont even know what the performance of Zen will be, much less the Zen APU. Think it is a bit premature to be touting it for MacBooks.
 

monstercameron

Diamond Member
Feb 12, 2013
3,818
1
0
Yes you could but this was a thread about Carrizo ()

you are missing the point. AMD's platform is supposed to compete on 2 factors, Price and GPU performance. With both factors not present is nearly any AMD power machine its value proposition is greatly diminished.

If you can but a laptop that is much faster than carrizo for the same price, it means that they failed to market this product.

This is very upsetting (don't know why I am this emotionally invested TBH) but it is a very solid product letdown by crappy implementations.
 
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