Intels latest "NUC" - Part 2 - Is it properly balanced in bandwidth capabilities?

[TheDarkKnight]

I was all gung-ho and ready to purchase one of the latest, albeit, lower-end models, of Intel's "NUC" product line, the $1XX N2820 based NUC. Model number DN2820FYKH0.

Now that I am over the wow-factor of the small size and the extra features I still think it's an awesome piece of technology. The size is right, the price is right, but something still doesn't seem right to me. It seems to me that the smartest thing to do when building anything in life is to match up the proper components of any product in a balanced manner. The parts that come together as a "whole" should complement each other and not hold each other back.

In my first post I was questioning the decision to only offer the least powerful version of Intels "HD Graphics" in this latest NUC.

A few smart individuals cleared up some of my pessimism by educating me on the fact that even though Intels latest "NUC" only has "HD Graphics" that they are not my grandfathers "HD Graphics" so to speak. There are many improvements over previous generations. One of the most impressive to me, personally, being the maximum theoretical bandwidth. So I am very grateful for that information.

However, in my obsessive compulsive quest to make sure I understand exactly what I am getting for my money I have come up with another question I am hoping someone can clarify. When reading over the description of the latest NUC N2820 one part of the description hit me like a ton of bricks.

"Single channel SODIMM DDR3L 1066/ 1333 MHz, 1.35V"

Single channel...did I read that right? Single channel? Does that not severely cripple the "HD Graphics" component of the "NUC"? An article on www.wikipedia.org shows the theoretical maximum "Memory Bandwidth" for 7th generation "HD Graphics" to be 25.6GB/second. If we bought a single stick of the fastest DDR3L memory that this N2820 can utilize it would be running at 1333MHz(PC3-10600) which offers a maximum theoretical memory bandwidth of only 10.6GB/sec or 21.2GB/sec if there were a second memory channel running in dual-channel memory mode.

Now, if this unit had been released with two memory channels capable of running dual-channel memory mode it would have been a very balanced product in my eyes. But releasing this product with a single memory-channel seems illogical to me. Now it may come down to factors that just don't make economic sense for Intel. In other words, its probably cheaper for Intel to release unbalanced parts so that these units can be offered at incredibly reduced prices from past generation units. If that's the case, then so be it. I can accept that given the price is so low.

I am through bashing Intel like I did in the beginning. I think the second generation of "NUC"s are much better than last and will only get better. But for me personally, having a GPU that can go 120MPH(25.6GB/sec) and only being able to use it at less than half of that speed(10.6GB/sec) because of only having a single-channel memory controller really bugs me. But I am a computer nerd. I am sure 95% of the population will love this product.

**EDIT**: Just one last comment. If my description of the relationship between the GPU and memory bandwidth of this product is inaccurate, somebody, please speak up and let me know.

 

[ShintaiDK]

http://forums.anandtech.com/showthread.php?t=2366996

 

[TheDarkKnight]

http://forums.anandtech.com/showthread.php?t=2366996

That thread was asking if the execution units were powerful enough to saturate the graphics memory bandwidth.

This thread is asking if the actual system memory is powerful enough to saturate the graphics memory bandwidth.

So, it's technically a different question. I could have asked at the end of the thread or I could have posted a new thread. It basically seemed like a coin toss so I posted a new thread.

I know, after reading questions all day they all start to blur together and look the same, right?

 

[ShintaiDK]

If 25GB/sec is good enough for 20 and 40EU at 1200 and 1300Mhz. What do you think 8.5GB/sec is to 4EUs at 756Mhz?

 

[TheDarkKnight]

If 25GB/sec is good enough for 20 and 40EU at 1200 and 1300Mhz. What do you think 8.5GB/sec is to 4EUs at 756Mhz?

Your talking about execution units again. I am not sure what that has to do with the relationship I am talking about now. 25GB/sec might be more than enough bandwidth to handle whatever 10 execution units can throw at it(not sure why you used the number 4 as I have previously and am currently talking about 7th generation HD Graphics which uses 10 execution units).

But the fact is, that the graphics memory of an iGPU relies entirely on system memory. The system memory in this N2820 NUC unit "appears" to be single channel memory capable of a theoretical maximum memory bandwidth of 10.6GB/sec. That is nowhere *near* 25GB/second.

 

[ShintaiDK]

BayTrail as the NUC you list got 4EUs.
GT1 Celeron and pentium Core got 10EUs.
GT2 got 20EUs and GT3/GT3e 40EUs.

All the exact same GPU. Just different amount of EUs and clockspeed.

And the memory in the NUC you list is 8.5GB/sec.
http://www.intel.com/content/www/us/en/nuc/nuc-board-dn2820fykh.html

 

[TheDarkKnight]

BayTrail as the NUC you list got 4EUs.
GT1 Celeron and pentium Core got 10EUs.
GT2 got 20EUs and GT3/GT3e 40EUs.

All the exact same GPU. Just different amount of EUs and clockspeed.

And the memory in the NUC you list is 8.5GB/sec.
http://www.intel.com/content/www/us/en/nuc/nuc-board-dn2820fykh.html

I see you are correct. That link says that the memory is "downclocked" to 1066MHz. There's another "thumbs down" for me. So the N2820 has an iGPU capable of producing 25.6GB/second of data. And it has a single-channel of system memory capable of handling 8.5GB/sec of data. Yikes!!!!!

So to summarize, the graphics capabilities are much more powerful than can be utilized by the speed of the general system memory.

EDIT: I am guessing those execution units translate, somehow or another, directly into GFLOPS. Wikipedia shows the GFLOPS that each generation of Intels HD Graphics can produce but no numbers for the Bay Trail series just yet.

Also, wikipedia shows that the 7th generation of HD Graphics "should" have 10 execution units. What did they do take the chip out in the back alley and break a few legs? They could have left that alone. With a maximum theoretical system memory bandwidth of 8.5GB/second, hell, they could probably put 40EUs on a budget chip. The end-user still isn't going to see any of that benefit.

 

[ShintaiDK]

I see you are correct. That link says that the memory is "downclocked" to 1066MHz. There's another "thumbs down" for me. So the N2820 has an iGPU capable of producing 25.6GB/second of data. And it has a single-channel of system memory capable of handling 8.5GB/sec of data. Yikes!!!!!

So to summarize, the graphics capabilities are much more powerful than can be utilized by the speed of the general system memory.

EDIT: I am guessing those execution units translate, somehow or another, directly into GFLOPS. Wikipedia shows the GFLOPS that each generation of Intels HD Graphics can produce but no numbers for the Bay Trail series just yet.

The N2820 cant do 25.6GB/sec. It can do 17GB/sec.
http://ark.intel.com/products/79052/Intel-Celeron-Processor-N2820-1M-Cache-up-to-2_39-GHz?q=N2820

 

[TheDarkKnight]

The N2820 cant do 25.6GB/sec. It can do 17GB/sec.
http://ark.intel.com/products/79052/Intel-Celeron-Processor-N2820-1M-Cache-up-to-2_39-GHz?q=N2820

I believe you but how did you get that information from the link you posted? I followed it and couldn't find those numbers.

 

[ShintaiDK]

I believe you but how did you get that information from the link you posted? I followed it and couldn't find those numbers.

Just look under memory specification.

Memory Types DDR3L-1066
# of Memory Channels 2

 

[TheDarkKnight]

Just look under memory specification.

Okay, I see what you are saying now. But that was the point of my entire post. When you say the N2820 can't do 25.6GB/sec you are talking about the system memory. But the 7th generation of "HD Graphics" are capable of 25.6GB/sec. That was the whole point I have been trying to illuminate here for *everybody* to understand. The internal parts are not evenly matched in their speeds.

What's even more strange though, is that the last link you posted shows that it would have been possible for Intel to provide two memory slots on their latest NUC but they chose not to on this specific model. So instead of offering consumers a potential of 17GB/sec of system memory bandwidth, it has been crippled to 8.5GB/sec because having of only offering a single channel memory slot.

They will probably release another "NUC" based on the same CPU, the N2820, in a few months with two memory slots for a small price premium. It only makes sense to me.

It's also rather deceptive, at least to me anyway, to show that the N2820 based NUC can use 1333MHz DDR3L 1.35V memory but then it get's "downclocked" to 1066MHz. I guess that's okay if you already have the memory and you don't wanna purchase new memory. But it still cripples the value of your faster ram right off the bat.

Oh, and just to let everybody know here. Everything I am trying to understand here has been going on for an ungodly number of years. It's just now that I am beginning to put all the pieces together. So, as they say in "Star Wars", "nothing to see here, move along, move along". I just happen to be taking an extreme interest in the details of my purchases as of lately.

I have generally always bought all of my own computer parts and built my own systems based upon my preferences of brand names. So the unbalanced parts I may have purchased I was, for the most part, completely responsible for. When you have someone like Intel putting together a system for you, you would think it would be as balanced as possible. But as someone else pointed out in the prior thread, - it's marketing 101.

 

[lakedude]

Mr Knight it seems to me like you are trying to make the NUC something it is not. Compromises need to be made to stay within given power and monetary budgets.

Those little NUCs are amazing for what they are. They are great for HTPC use and the like. They are low power devices, not high performance gaming rigs.

If you need something with dual channel memory there are plenty of choices. Heck why stop there? Maybe you get yourself an "extreme edition" system with a triple channel memory interface just to make sure you have enough bandwidth...

 

[ShintaiDK]

But the 7th generation of "HD Graphics" are capable of 25.6GB/sec. That was the whole point I have been trying to illuminate here for *everybody* to understand. The internal parts are not evenly matched in their speeds.

You seem to confuse/misunderstand everything. Its the IMC on the Core series CPUs that handles 25.6GB/sec when using the officially highest supported memory with 1600Mhz on the models that support 1600Mhz.

The GPU sits on the ringbus.

 

[dave_the_nerd]

If you're purchasing a NUC for a performance critical application, perhaps you should not have gotten the cheapest Atom-powered one.

FWIW, i have an Atom based NanoPC as an HTPC and it works fine, even with "only" single channel DDR3 and "crappy" integrated graphics.

 

[FwFred]

Hi Dave, it may help if you describe what you want the NUC to do for you.

 

[TheDarkKnight]

You seem to confuse/misunderstand everything. Its the IMC on the Core series CPUs that handles 25.6GB/sec when using the officially highest supported memory with 1600Mhz on the models that support 1600Mhz.

The GPU sits on the ringbus.

Yes, I do get confused sometimes when trying to sort this all out. I had a feeling my last post was in error. It's constantly referring back to the article on Wikipedia that gets me in trouble. They show multiple generations of Intel HD Graphics and what the different capabilities are. It gets confusing to me but I think I got a handle on it now. Thanks for helping me understand.