The ESRAM in Durango as a possible performance aid

[Urian]

I am very bad traslating from spanish to english, but if any of you can help in my investigation.

http://josepjroca.wordpress.com/2013/05/25/xbox-one-overview-esram-ampliado/

 

[Ninjaprime]

This line from the Haswell article was interesting:

Intel claims that it would take a 100 - 130GB/s GDDR memory interface to deliver similar effective performance to Crystalwell since the latter is a cache. Accessing the same data (e.g. texture reads) over and over again is greatly benefitted by having a large L4 cache on package.

So, if Intels 50GB/s is equal to 100-130GB/s because of its low latency and cache perks, assuming Xbone's is a cache as well, does that mean Xbone's 102.4GB/s is equal to 205-270GB/s?

 

[Betanumerical]

This line from the Haswell article was interesting:

So, if Intels 50GB/s is equal to 100-130GB/s because of its low latency and cache perks, assuming Xbone's is a cache as well, does that mean Xbone's 102.4GB/s is equal to 205-270GB/s?

The Haswell cache is 50GB/s each way, making it 100GB/s in total. So no.

 

[TheWretched]

And it's 4 times as big, making the cache much ... well bigger.

 

[XpiderMX]

I am very bad traslating from spanish to english, but if any of you can help in my investigation.

http://josepjroca.wordpress.com/2013/05/25/xbox-one-overview-esram-ampliado/

Not the best option for translation but...

 

[Gubbi]

Why is Anand so hung up on the cache thing? I dont think the ESRAM is a cache, so is Xbox doomed?

Because the CPU can use the cache when the GPU isn't And no, the XB1 isn't doomed.

Cheers

 

[Michellstar]

we are forgetting that crystalwell also has to serve 4 i7 cores, and ESram in Durango is for the GPU

 

[Rangers]

we are forgetting that crystalwell also has to serve 4 i7 cores, and ESram in Durango is for the GPU

err, there's also 128mb vs 32. pretty sure it can handle the difference.

 

[Love_In_Rio]

we are forgetting that crystalwell also has to serve 4 i7 cores, and ESram in Durango is for the GPU

Can´t X1´s cpu put data and retrieve data from ESRAM?. One thing is that it doesn´t consider it a L3 automatically, but i think it will be able to do it manually...

 

[fehu]

Can´t X1´s cpu put data and retrieve data from ESRAM?. One thing is that it doesn´t consider it a L3 automatically, but i think it will be able to do it manually...

If I understand, to read them again the cpu has to put the data on the main memory again, so adding latencies instead of reducing them

 

[blakjedi]

If I understand, to read them again the cpu has to put the data on the main memory again, so adding latencies instead of reducing them

move engines

 

[fehu]

move engines aren't separated from the cpu?

 

[Love_In_Rio]

If I understand, to read them again the cpu has to put the data on the main memory again, so adding latencies instead of reducing them

"The GPU has a direct non-coherent connection to the DRAM memory controller and to ESRAM. The GPU also has a coherent read/write path to the CPU’s L2 caches and to DRAM.". Well, then it seems the GPU can read and write from the CPU L2 but nothing in the other way is mentioned, so maybe yes, CPU can read from DDR3 and not from ESRAM directly.

 

[blakjedi]

"The GPU has a direct non-coherent connection to the DRAM memory controller and to ESRAM. The GPU also has a coherent read/write path to the CPU’s L2 caches and to DRAM.". Well, then it seems the GPU can read and write from the CPU L2 but nothing in the other way is mentioned, so maybe yes, CPU can read from DDR3 and not from ESRAM directly.

AFAIK CPU has "direct" access to the ESRAM through the graphics memory controller over a 30GB/link to the Northbridge

 

[blakjedi]

move engines aren't separated from the cpu?

yes they are. but you wouldnt keep adding latencies because the activities of the move engines are independent of both CPU/GPU and simultaneously use the available memory bandwidth of the system.

"You may wonder what happens when the GPU is busy copying data and a move engine is told to copy data from one type of memory to another. In this situation, the memory system of the GPU shares bandwidth fairly between source and destination clients. "

-http://www.vgleaks.com/durango-memory-system-overview/

 

[Betanumerical]

yes they are. but you wouldnt keep adding latencies because the activities of the move engines are independent of both CPU/GPU and simultaneously use the available memory bandwidth of the system.

"You may wonder what happens when the GPU is busy copying data and a move engine is told to copy data from one type of memory to another. In this situation, the memory system of the GPU shares bandwidth fairly between source and destination clients. "

-http://www.vgleaks.com/durango-memory-system-overview/

Yep which is kinda the entire point of DMA units after all.

 

[Michellstar]

err, there's also 128mb vs 32. pretty sure it can handle the difference.

I know, i know

Just pointing out that even intel thinks that 128mb is overkill for their configuration (32mb would be enough they reckon) but wanted to be future-proof

Anyway, we are just seeing the massive advantage in process that Intel has over everybody else, they manage to fit 128mb in 84mm^2 on 22nm.

Moreover, Crystalwell is on a separate die, AMD/Ms for Durango followed the apu route, External EDRAM wasn´t a possibility??


Well, I would love to see comparisons between GT3 parts with or without crystalwell, same config of course

 

[blakjedi]

What was IBM's role in the design of Durango?

 

[3dilettante]

Moreover, Crystalwell is on a separate die, AMD/Ms for Durango followed the apu route, External EDRAM wasn´t a possibility??

In some form, it was possible, just undesirable.
It's an extra component that would likely be an added expense for most/all of Durango's manufacturing life. Also, absent some of Intel's engineering to make it worthwhile, it would likely be inferior. (edit: e.g a high-speed bidirectional bus on-package)

What was IBM's role in the design of Durango?

There's no mention of any significant role.

 

[Cyan]

The Xbox One is the fastest ever pre-ordered console at ASDA -UK-.

Even so, the most curious thing about it is that the eSRAM is being publicized as one of the main features and technical accomplishments of the console, which is unheard of, afaik (also the text has been written by a woman):

The console of the future is (nearly) here! The Xbox One promises to be the only entertainment system you need in your home, delivering the ultimate experience like nothing before, its innovative technology is rivaled only by its iconic design.

Gone are the days of trying to find the shows you love, you can totally personalise this console by creating your very own channels, pinning all your favourite shows and apps to one place. What’s more, you can split your TV screen and seamlessly jump from gaming to TV to Skype and back again, all on one console, making switching inputs a thing of the past.

The combination of its CPU, GPU and ESRAM means you have nothing short of a lightening fast supercomputer in your living room; with the words ‘Xbox on’ your console will recognize your voice and instantly come to life, meaning no more loading time. You can start playing games immediately as updates install in the background so your entertainment is never interrupted and always up to date.

With the arrival of this amazing console comes the new generation of Xbox Live, connecting you to thousands of games, songs, TV shows, movies and sports hosted on the wider Xbox community.

So what are you waiting for? This entertainment system guarantees to push all the right buttons and you can reserve yours today at Asda for just £20.
Visit http://direct.asda.com/Xbox-One-Pre-Order-%C2%A320/003799558,default,pd.html to place your order.

Contact Rosanna.Williams@freud.com or call 0203 003 6537 for more information

Full article and text here:

http://www.mcvuk.com/press-releases/read/pre-order-the-xbox-one-at-asda/0116510