News & Rumors: Xbox One (codename Durango)

Does anyone know an answer to that?

 

The new Xbox isn't limited to a measly 68GB/s.

 

Because as noted, you dont use 5GB per frame. There's your answer.

176 GB/s divided by 60 FPS=2.9 GB/s.

Guess PS4 will never have any 60 FPS games then...

Also, technically you can get up to 170 GB/s, right? The ESRAM is pretty important. This gen PS3 had two ~25 GB/s busses to the GPU, one to XDR one to GDDR, ~50GB/s. 360 only had one ~20 GB/s bus, so less than half the bandwidth Yet it still held up fine because of the EDRAM. The ESRAM can take BW load off the main BW, just as EDRAM took BW load off the main bus for 360. All the load in a unified no EDRAM architecture must fall on the main bus.

Anyways, I dont know how much is usable on Durango but I do know devs wanted some of the OS reserves back, so it IS more than 5GB. And RAM is an order of magnitude faster than a hard drive, so it is always useful, no exceptions. If worst case you can do absolutely nothing else with it (unlikely), you can use it as a cache to reduce loading.

Also just to quibble, 68/30=2.26, not 2.0

 

I've always kept it in the realm of possibilities because of the Yukon Roadmap, and also for the AMD/IBM team that MS assembled. I also consider it because MS took direct action in seeing to Yukon's removal from various sites. I believe that was a significant move on their part.

I've repeated this more than a few times so I hope people will forgive me for sounding like a broken recording. lol

I honestly don't have any specific requisites on how it would be configured, APU+APU, APU+GPU, or even something reflecting the AMD patent for APU+APD. I'm naturally for whatever works graphics and performance wise.

In either case however it works out or DOESN'T work out, I look forward to hearing the un-mingled truth. I want to know how they did it, or didn't do it. It's all very interesting to me how this hardware puzzle will finally come together.

 

Of course not, but the only bus to the large data storage is. Sure the eSRAM is fast (and useful!) but its only so large.

 

The 8GB are, you cant use those 102GB/s to suddenly get more than 2 GB per frame.
The eSRAM is nice for render targets, but with only 32 MB, there is not enough room for much else.

I asked this question, because i dont really see the benefit to increase the amount of ram available to the dev. Sure, u can use the rest as cache, but i doubt going from 5 to 6 or 7 GB matters much in that regard.

Of course u can use 3+GB for system memory, but i dont really know why a CPU needs that much data.

 

The ESRAM could do FB operations, leaving the main bus just for other things.

A unified would need to use the main BW for everything.

Exactly the same as 360 setup which worked really well, even seemingly better than PS3 with over 2X the main BW, in some cases. Because PS3 had to do FB in main RAM.

There are some games, some call of dutys that I recall, that actually had higher res effects on 360 with half the main BW.

What's left is mainly textures, I suppose.

In a unified, you will have much less of the main bus for textures than you would if you had a pool of fast RAM too.

Well apparently the devs do, because they asked for more than 5GB in Durango according to what I heard.

I expect Microsoft will go to at least 12Gb possibly 16GB on the 21th...it's just such a Microsoft thing to do. A hardware response is common for them.

 

Do 8Gb DDR3 Chips even exist? Because with the current 4Gb chips they would have to put 32 Chips on the board (for 16GB), dont think thats very feasible.

 

i dont know these details. i just know 8gb gddr5 wasnt considered feasible for ps4 either.

my guess is they just special order something, like sony did for ps4.

I did some basic googling and I think there is 8Gb LPDDR chips, for what that's worth. Seems possible for DDR3 if somebody wants it, guessing there is just not a market reason just yet.

http://hothardware.com/News/Samsung-Reveals-Industrys-Highest-Density-LPDDR2-DRAM/

There is 8Gb DDR3 listed here too if it's the same thing

http://www.micron.com/products/dram/ddr3-sdram

 

Yes.

 

The point I was trying to get across is that you.

A. You have to use the DDR3 bus to even something into the eSRAM (for the first read at least)
B. If you have a file/data thats larger then 32mb or your going to need it multiple times in the same frame at different times your probably not going to get near the peak bandwidth of the eSRAM.

I will admit I could have phrased it better though.

 

Is that really going to be such a big deal though, considering that anytime any of the main ram is being directly utilized for specific game assets, the performance of the GPU overall is always going to be assisted by the ESRAM bandwidth? I don't think the game assets necessarily have to be stored in ESRAM in order for game performance to still benefit from the ESRAM bandwidth.

 

If the theres nothing in the eSRAM, and if assets you are looking for are not in the eSRAM then you do not get any benefits from it at all, you need to have your assets in there for it to be of benefit.

 

Well, then i can definitely see MS doing that ( though as i said, i doubt theres a great benefit compared to 8GB)

Oh i wasnt talking about game perfomance.
I was just talking about useable data per frame, which is limited by the bandbwidth of main ram. (Of course 2 GB per frame ist still plenty for the GPU to use)

The eSRAM is pretty useful for any operation that needs a lot of fast reads/writes of small data (thats also where the low latency should be very useful).
I can see some nice alpha particle effects.

 

ESRAM bw is not shared with the CPU.

 

As noted, you need the stuff you want to work on to be present in the embedded memory (we don't actually know for sure it's SRAM so I'm not going to be calling it that, and calling SRAM "ESRAM" is just stupid, because SRAM is SRAM; technically ANY SRAM on a die would have to be called "ESRAM" then and that would be nothing but dumb.) Also, any copying of assets back and forth in the system is going to count double against the total available bandwidth; once for main RAM and once for embedded, each way. In a system without embedded memory there wouldn't be a need to copy anything anywhere of course.

Embedded RAM is a powerful resource, but it's not magic, and it's not without its own issues either; there's no such thing as the one perfect, ideal solution in this world, or at least not with anything which is as complicated as a modern gaming console.

 

No you don't.

Shadowmaps can be directly generated in ESRAM and directly consumed from it, same with G-buffer data.

You might want to store your texture atlas in ESRAM, updates to which would cost the same as writes to external RAM (and typically amortized over many frames).

Cheers

 

You make an excellent point of course, but I thought I was fairly obviously referring to already existing assets; sorry if I was being unclear there!

 

+1 these posts. The posts were bad before, but they were getting worse the closer the 21st came. Glad to hear I wasn't the only one who had issue with them.

Tommy McClain

 

Who makes 8Gb at 2133 ?