The ESRAM in Durango as a possible performance aid

i know i'm pretty much uninformed on how any of this stuff works so bear with me. but i thought esram's bandwidth was based on the clocks of the gpu it was embedded on when talking about xbox one. someone said bidirectional so that means sending and receiving right? so is it 133GB/s both ways or is it 66.5GB/s both ways?

My pet theory is that the 102 GB/S might be the limit of a 1024 bit buss at 800 MHz. (0.8*1024 = 102).

*Or* it might be the limit of the clients writing to the eSRAM.

You might not be able to use any more if the clients can not supply or consume more that that.



*Maybe* unusual situations might be possible depending on the eSRAM, buss, cache and client plumbing. What happens with one client writing and another reading? Perhaps that is where the other numbers come from.



950 MHz @ 1024 bits would give 120/121.6 GB/Sec and 1050 MHz @ 1024 bits would give 134.4 GB/Sec.



Just pure speculation, so don't get upset. Not sure how high the clock can go or how high the 100 W can go.



I expect 1024 bits wide is the number. Don't know about clock changes. Know less about simultaneous read/write. Might depend on what sort of controller/interface and whether or not there is some sort of cache in front of the eSRAM. I didn't consider that originally but if there are varying BW numbers I wonder (maybe?)
 
so wouldn't that mean in order for the esram to be 133gb/s like digital is reporting the gpu has to be clocked at 1050Mhz? wouldn't people be talking about something so significant?
 
so wouldn't that mean in order for the esram to be 133gb/s like digital is reporting the gpu has to be clocked at 1050Mhz? wouldn't people be talking about something so significant?

I really don't know. I could see it as possible, but without knowing way more about how it is setup it would be BS for me to say yes or no. There are many possibilities about how it is designed and far too little info is available for me to make any solid conclusion.

That said, the numbers seem to fit.

I don't think an up clock is hard. I am in the camp that says "not such a big deal". I think 12GB is harder but not impossible. But from 800 MHz to 1050 MHz is a pretty large step. I would love that if it can be done. I am a bit incredulous that both Sony and MS are only willing to spend 100W and a bit under 100W for 3.X and 5 billion transistor super massive APU chips. I don't know what either were thinking. I think expecting a 100W and 8?W design to last nearly 10 years is borderline crazy. I can easily see using up 100W with 12CU and 8 cores. I have no idea how Sony plans to clock 18CU and 8 cores on 100W or a bit less. I would expect 140W on PS4 SoC if Xbox One is 100W. But the FCC power supply info does not line up with that.

Now I would not suggest 200W for that Tahiti sized chip either. But I would like to see 140W. Or at *least* 125W.
 
i would think a 250Mhz clock increase on the gpu would be a pretty big thing. i mean i dont think such high uplocks like that are normal this late in the game. i'm also why only df is reporting this and nowhere else? i mean something like finding basically 30gb/s more bandwidth should be something many sites would write about right?
 
I really don't know. I could see it as possible, but without knowing way more about how it is setup it would be BS for me to say yes or no. There are many possibilities about how it is designed and far too little info is available for me to make any solid conclusion.

That said, the numbers seem to fit.

I don't think an up clock is hard. I am in the camp that says "not such a big deal". I think 12GB is harder but not impossible. But from 800 MHz to 1050 MHz is a pretty large step. I would love that if it can be done. I am a bit incredulous that both Sony and MS are only willing to spend 100W and a bit under 100W for 3.X and 5 billion transistor super massive APU chips. I don't know what either were thinking. I think expecting a 100W and 8?W design to last nearly 10 years is borderline crazy. I can easily see using up 100W with 12CU and 8 cores. I have no idea how Sony plans to clock 18CU and 8 cores on 100W or a bit less. I would expect 140W on PS4 SoC if Xbox One is 100W. But the FCC power supply info does not line up with that.

Now I would not suggest 200W for that Tahiti sized chip either. But I would like to see 140W. Or at *least* 125W.

You could spend 100 watts on a single core @ 6ghz or 100 watts on 8 cores @ 2ghz, 6 vs 16. With Multi threading the 8 core chip can perform far and above the higher clocked part.

Keep in mind Kaveri/Jaguar is probably the 1st AMD design to fully utilize resonant clock mesh so the theoretical performance vs past processors could be up to 130%

Developers will be heavily focused on multithreading and almost no focus on single threaded IPC in this next generation of multiplatform games.
 
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