Question Speculation: XBox series S SoC info...

LightningZ71

Golden Member
Mar 10, 2017
1,627
1,898
136
It is a rather solid rumor that MS has scheduled a second version of the new XBox that is targeted at more modest performance targets, mainly 1080p video, with 8GB ram and 4TFlop graphics power. My question is around what actual processor will be used for this?

I speculate that the processor used won't be a product of the semi-custom group, and will, instead, be a custom binned Van Gogh APU.

Why?

I believe that the suggested performance targets are achievable with Van Gogh as it is speculated to be configured. The CPU and RAM side are the easy parts. It's hitting the 4 Tflop of graphics performance that's going to be the biggest hurdle. Currently, that is roughly the throughput of the 5500m. So, the question is, can they integrate enough RDNA2 CUs into an APU? Looking at what they've done with Vega 8 on rwnoir, they seem willing to go with fewer CUs at higher clock speeds. If we use the 5500 as a ballpark, doubling the CUs in the APU from Renoir gives you 16CUs. With a modest clock speed bump, that's in the ballpark of 4 Tflop of GPU throughput. With a process Change to N5, that should be able to live in roughly the same die size as Renoir.

The next issue is RAM throughput. Full spec, dual channel DDR5 is expected to provid about 100 GB/ sec of throughput. While that is about half of the throughput of the 5500m, it's still enough to keep up with the demands of a reasonable texture quality setting.

Finally, we have I/O. The big deal there with the PS5 and XBoxsX is their need to stream vast amounts of data to keep up with the needs of high quality 4K textures. If we allow for more modest texture quality, both the active memory footprint and the second by second data access needs shrink significantly, allowing the use of a commodity, cacheless NVME drive to be more than sufficient.

Any thoughts?
 

NTMBK

Lifer
Nov 14, 2011
10,208
4,940
136
No way in hell would dual channel DDR5 suffice. This is the replacement for a console which had 256-bit DDR4, and STILL needed a custom ESRAM buffer to provide enough bandwidth. I'd expect 192-bit or 256-bit DDR5.

Of course, it could still be the same silicon as Van Gogh, if there are unused memory controllers on the die. AMD has precedent here- their Tonga chip had a 384-bit controller, but most (all?) SKUs shipped only used 256 bits.
 
  • Like
Reactions: Tlh97

blckgrffn

Diamond Member
May 1, 2003
9,110
3,029
136
www.teamjuchems.com
Same CPU (cores, threads, clock speeds) as Series X with ~60% of the memory bandwidth as we cut the memory in half (Series X has a wonky memory bandwidth layout).

¯\_(ツ)_/¯

I've figured Lockheart or whatever it's code name will target 1080p (rumors kept saying 2k resolutions, why?) and not have UHD and be used to have the lowest possible BoM to push the current xbox skus out of production/relevancy.

That said, I would think they would just use the same custom CPU/GPU type packaging and the same storage, as you can already buy the storage add in cards. I mean, they are probably forecasting selling 10M+ of the low end variant in the next three years? I don't see why they would create more variety than absolutely needed. The main SKU will be for those that want the best possible graphics and a UHD drive.

That hopefully, you know, supports Dolby Vision for UHD playback (across all UHD equipped Xbox SKUs). Because that is a glaring omission right now and keeps it off being anywhere near the top of UHD playback recommended device lists where you would think it would dominate (as the PS3 has done so well for so long as a premier BluRay player).

Since this is a complete speculation thread, there, you have mine.
 
  • Like
Reactions: Tlh97

firewolfsm

Golden Member
Oct 16, 2005
1,848
29
91
It could also be salvaged Series X SOCs which have defective memory controllers and/or CUs. Or a combination of salvaged and custom cut down chips. I'm guessing this is the case because the Series X SOC has other additions (texture compression being one) which the S will need to match for feature parity.
 

LightningZ71

Golden Member
Mar 10, 2017
1,627
1,898
136
No way in hell would dual channel DDR5 suffice. This is the replacement for a console which had 256-bit DDR4, and STILL needed a custom ESRAM buffer to provide enough bandwidth. I'd expect 192-bit or 256-bit DDR5.

Of course, it could still be the same silicon as Van Gogh, if there are unused memory controllers on the die. AMD has precedent here- their Tonga chip had a 384-bit controller, but most (all?) SKUs shipped only used 256 bits.
The original XBox One had 68 GB/s c of bandwidth from it's DDR3, and the ESRAM cache topped out at ~109GB/sec of throughput.

The XB1X went to GDDR5 and a widder bus, but was also targeting 4K performance. It also got rid of the ESRAM cache.

It is perfectly believable that a system with the same throughput in RAM as the ESRAM cache in the XBox one can achiev the same output quality or bette, especially when th CPU cores and storag I/O numbers will be drastically faster. Heck, the jaguar based CPU in the XB1 didn't even have an L3 cache!
 
  • Like
Reactions: Gideon

jpiniero

Lifer
Oct 1, 2010
14,510
5,159
136
It could also be salvaged Series X SOCs which have defective memory controllers and/or CUs. Or a combination of salvaged and custom cut down chips. I'm guessing this is the case because the Series X SOC has other additions (texture compression being one) which the S will need to match for feature parity.

Salvage would be too expensive. A cut down version of the XSX would make sense.

At the same time, MS has been pretty vocal about BC so I don't know if having feature parity is necessary. If a dev is targeting Lockhart, you may as well include the XBox One X in that target.
 

LightningZ71

Golden Member
Mar 10, 2017
1,627
1,898
136
I would also imagine that power efficiency is also a big consideration for Lockhart. Lower Powe, less to cool, smaller power supply, all means a smaller box and less expensive to make.

What if Lockhart is mobile, like the Switch?
 

blckgrffn

Diamond Member
May 1, 2003
9,110
3,029
136
www.teamjuchems.com
Salvage would be too expensive. A cut down version of the XSX would make sense.

At the same time, MS has been pretty vocal about BC so I don't know if having feature parity is necessary. If a dev is targeting Lockhart, you may as well include the XBox One X in that target.

I think it would make the most sense for newly launched SKUs to have at least feature parity with those that have launched in the past.

I mean, are they going make RT a Series X "only" premium feature?

The storage revolution only is a revolution if there are enough clients out there that support it.

Cut down GPU and ram will lower the power profile. I think cutting the optical drive and all the licenses required for playing those formats from media would likely cut down on the cost.

A Switch Box? That seems really far fetched given the scaling and power issues x86 & RDNA2 would have to tackle. The power consumption of the switch is ~10W. Even a 15W chip is 50% more power hungry and requires that much more battery to get "portable" usability... Also, it would have to incorporate some sort of NVME storage... it seems like it would be a very expensive part when compared to the switch.
 

LightningZ71

Golden Member
Mar 10, 2017
1,627
1,898
136
I admit that making a mobile XBox is really deep in the woods, however, Nintendo has definitely proven that such a device can gain traction in the market. Nintendo noted that the vast majority of Switch users use their switch undocked. These are people that paid north of $250 each for a system that was very compromised, yet still manages to deliver a decent player experience for most titles while mobile. What if Microsoft was targeting something perhaps 10% larger than switch, with a 1080p display, that was fully compatible with the entire catalog of XBsX games? At 5nm, with rather modest goals, and a few years more battery development as compared to Switch, with a eye to break even, I believe that such a device is possible at a price point below $400. Remember, there are a lot of people that willingly spend 2-3x that on mobile phones.
 

SPBHM

Diamond Member
Sep 12, 2012
5,056
409
126
likely the same CPU (perhaps a few hundred MHz lower?), memory bandwidth, probably 128bits GDDR6 like the 5500XT?
SSD, perhaps lower capacity? lower speed (but still far ahead of sata SSDs)?

I think it makes a lot of sense if the PS5 and series X are too expensive and 4K focused.

if they keep the SSD and CPU close enough, scaling back the graphics/resolution is less problematic, but scaling games from a "16GB" to "8GB" platform might lead to some unfortunate compromises already...
 

jpiniero

Lifer
Oct 1, 2010
14,510
5,159
136
The storage revolution only is a revolution if there are enough clients out there that support it.

MS is already compromising this by pushing BC. I think the games that truly take advantage might have to be PS5 exclusives for the time being.

I like the Switch idea a lot actually but seems unlikely.
 

LightningZ71

Golden Member
Mar 10, 2017
1,627
1,898
136
likely the same CPU (perhaps a few hundred MHz lower?), memory bandwidth, probably 128bits GDDR6 like the 5500XT?
SSD, perhaps lower capacity? lower speed (but still far ahead of sata SSDs)?

I think it makes a lot of sense if the PS5 and series X are too expensive and 4K focused.

if they keep the SSD and CPU close enough, scaling back the graphics/resolution is less problematic, but scaling games from a "16GB" to "8GB" platform might lead to some unfortunate compromises already...

I don't feel that the drop from 16GB to 8GB will be too big of an issue. Given the targeting of the anaconda at 4K/8K with high quality textures, scaling down to 1080P with more modest texture quality goals should be able to fit there nicely. I'm more concerned about mobile thermals and how they will manage ray tracing (or if it gets excluded completely from the S). The drop in texture quality drastically reduced the need for system memory and also the volume of memory that needs to be streamed from the SSD.
 

blckgrffn

Diamond Member
May 1, 2003
9,110
3,029
136
www.teamjuchems.com
MS is already compromising this by pushing BC. I think the games that truly take advantage might have to be PS5 exclusives for the time being.

I like the Switch idea a lot actually but seems unlikely.

They are only really promising it (keeping the One relevant for all titles) for two years. Also, we might see pretty different games for One S/X and for the new hardware in terms of loading times & animations. I mean, at some point you treat them like two different release targets and don't just rely on BC to get your games to run.

Relying on BC for new/post Series X games is like thinking Apple won't recompile for ARM :D (make sure you aren't missing out on those huge threads here ;) )
 

firewolfsm

Golden Member
Oct 16, 2005
1,848
29
91
likely the same CPU (perhaps a few hundred MHz lower?), memory bandwidth, probably 128bits GDDR6 like the 5500XT?
SSD, perhaps lower capacity? lower speed (but still far ahead of sata SSDs)?

I think it makes a lot of sense if the PS5 and series X are too expensive and 4K focused.

if they keep the SSD and CPU close enough, scaling back the graphics/resolution is less problematic, but scaling games from a "16GB" to "8GB" platform might lead to some unfortunate compromises already...

I agree with you about the CPU, but with a reduction in resolution comes a reduction in memory consumption from graphics (RAM is combined for CPU and GPU). They just need it to approximately scale so the CPU has equal resources.
 

LightningZ71

Golden Member
Mar 10, 2017
1,627
1,898
136
I wasn't aware that Van Gogh was semi custom. I thought that it was more of a mobile focused APU from the main line that was one of two development branches for APUs. One branch was for improved 7nm with ZEN3 and Vega (Cezanne) and a second targeted at 5nm, but to reduce risk, kept the Zen 2 cores, but went with RDNA2 as it was always targeted for a 5nm version (Van Gogh)