By using this site, you agree to our Privacy Policy and our Terms of Use. Close

Forums - Microsoft - Insider Daily. DDR3 RAM inside Xbox One acts like DDR4 from 2014 PCs and really have 272 GB/s BW (Misterxmedia)

fatslob-:O on 15 September 2013
drkohler said:
fatslob-:O said:

Edit: BTW if your wondering what that arrow actually is, it is probably a way for the CPU to command how the esram will manage memory not a way for the cpu to access esram. Remember when the developers said that they have to manage the esram manually, well it has to be the cpu that controls the esram and not the gpu because it provides more flexibility.

I'm pretty sure the gpu is calling the shots, not the cpus, via the host guest gpu mmu. This dark green rectangle is pretty much the core component of the entire SoC as far as data flow is concerned. But it isn't even clear whether the esram is a scratchpad or a cache or something ms-specific. Alos notice the strange black arrow goes bus to bus, not component to component, so it is really a mystery


You have alot of people on the tech forums believing its scratch pad memory.

Edit: In any case since I don't see a direct link from the gpu cache to the cpu cache I'm willing to put my bets that the xbox is likely not a hUMA system.



Around the Network
Mr Khan on 15 September 2013

Everyone who posted a single-image reply in this thread, this is your warning. Do not do so again, as heads will roll next.



Monster Hunter: pissing me off since 2010.

prayformojo on 15 September 2013
Zekkyou said:
It will also have 6 secret GeForce Titans hidden under 3 decoy AMD cards. Each console will also come with 9 orphan children, who will continually throw nitrogen over your Xbox One to keep it nice and cool.

I can confirm this because my uncle is the head of Microsoft.


You win the internets sir lol.



Chevinator123 on 15 September 2013
Mr Khan said:
Everyone who posted a single-image reply in this thread, this is your warning. Do not do so again, as heads will roll next.





Mr Khan on 16 September 2013
Chevinator123 said:
Mr Khan said:
Everyone who posted a single-image reply in this thread, this is your warning. Do not do so again, as heads will roll next.



That one made me chuckle, i'll admit.



Monster Hunter: pissing me off since 2010.

Around the Network
richardhutnik on 16 September 2013
Mr Khan said:
Chevinator123 said:
Mr Khan said:
Everyone who posted a single-image reply in this thread, this is your warning. Do not do so again, as heads will roll next.



That one made me chuckle, i'll admit.

I would be tempted to do this:



Machiavellian on 16 September 2013
fatslob-:O said:
drkohler said:
fatslob-:O said:

Edit: BTW if your wondering what that arrow actually is, it is probably a way for the CPU to command how the esram will manage memory not a way for the cpu to access esram. Remember when the developers said that they have to manage the esram manually, well it has to be the cpu that controls the esram and not the gpu because it provides more flexibility.

I'm pretty sure the gpu is calling the shots, not the cpus, via the host guest gpu mmu. This dark green rectangle is pretty much the core component of the entire SoC as far as data flow is concerned. But it isn't even clear whether the esram is a scratchpad or a cache or something ms-specific. Alos notice the strange black arrow goes bus to bus, not component to component, so it is really a mystery


You have alot of people on the tech forums believing its scratch pad memory.

Edit: In any case since I don't see a direct link from the gpu cache to the cpu cache I'm willing to put my bets that the xbox is likely not a hUMA system.

Since that black line connects directly with the ESRAM, would that not mean that the ESRAM is probably used as a cache for the GPU and thus the CPU can read its contents making the system HUMA capable.



ethomaz on 16 September 2013

Machiavellian said:

Since that black line connects directly with the ESRAM, would that not mean that the ESRAM is probably used as a cache for the GPU and thus the CPU can read its contents making the system HUMA capable.

Every APU can do that and it is not hUMA... hUMA means you don't need to refresh the CPU-cache to see how the GPU mem is being used... in any APU I can access the GPU memory but I need to refresh my cache table before that.

That's what mean coehent... you don't need to update your cache table to see the latest updates made by GPU (or vice-versa).

So no... the CPU can access the eSRAM without hUMA... what will make it hUMA is if the CPU-cache table coherent with GPU-cache table for eSRAM... if you need to do a refresh everythime you will access the eSRAM then it is not hUMA... in fact it is NUMA.



fatslob-:O on 16 September 2013
Machiavellian said:
fatslob-:O said:
drkohler said:
fatslob-:O said:

Edit: BTW if your wondering what that arrow actually is, it is probably a way for the CPU to command how the esram will manage memory not a way for the cpu to access esram. Remember when the developers said that they have to manage the esram manually, well it has to be the cpu that controls the esram and not the gpu because it provides more flexibility.

I'm pretty sure the gpu is calling the shots, not the cpus, via the host guest gpu mmu. This dark green rectangle is pretty much the core component of the entire SoC as far as data flow is concerned. But it isn't even clear whether the esram is a scratchpad or a cache or something ms-specific. Alos notice the strange black arrow goes bus to bus, not component to component, so it is really a mystery


You have alot of people on the tech forums believing its scratch pad memory.

Edit: In any case since I don't see a direct link from the gpu cache to the cpu cache I'm willing to put my bets that the xbox is likely not a hUMA system.

Since that black line connects directly with the ESRAM, would that not mean that the ESRAM is probably used as a cache for the GPU and thus the CPU can read its contents making the system HUMA capable.

Hmmm the black line does not directly connect to the cpu cache but rather if you look at the diagram it connects to a the bus of a cache which leads me to believe it exactly doesn't snoop the cpu's L1 and L2 cache but hUMA also requires things like volatile cache tag lines to mark what has changed from either sides of a cache so that a coherent cache bus can send the changes to either the cpu or gpu cache. 



ethomaz on 16 September 2013

fatslob-:O said:

Hmmm the black line does not directly connect to the cpu cache but rather if you look at the diagram it connects to a the bus of a cache which leads me to believe it exactly doesn't snoop the cpu's L1 and L2 cache but hUMA also requires things like volatile cache tag lines to mark what has changed from either sides of a cache so that a coherent cache bus can send the changes to either the cpu or gpu cache.

Exactly... the difference between hUMA and NUMA is that the first you have the cache refresh in both (CPU and GPU) all the time (coherent)... in NUMA you need to refresh the cache before access the other memory (non-coherent), CPU need to update the CPU-cache to see all the latest GPU memory and GPU need to update the GPU-cache to see all the latest CPU memory.