Though possibly true, the realistic size of MS's SOC shows high and wide isn't that expensive, so why did Sony do something different? We have to wait and see what the final console BOMs are to know if there's some good rationale for the decisions or not.
Why thank you for giving me an opportunity to elucidate on something that came to mind after going through the PS5 GDC talk and the XBSX DF article.
It appears that Microsoft and Sony started development of their consoles with 2 different overriding guidelines.
Microsoft started off with the guiding principles of...
Because of that we see a XBSX case that may be significantly over-engineered for cooling because RDNA 2 turned out to be more power efficient than they expected.
Sony appears to have started with the guiding principles of...
- X power (watt) target.
- And focusing on how to ensure that the console can hit that target no matter what conditions (within reason) the console is subjected to.
- What are the things that they can really focus on that wouldn't significantly affect the power target?
- Storage is a really good starting point.
- Audio, something Sony were already interested in is another low hanging fruit.
- How do they achieve BC so that Microsoft doesn't have a competitive advantage in terms of keeping people in their ecosystem?
- Without as much abstraction as MS has or experience with supporting BC across a changing landscape of hardware, this meant the hardware had to do the lions share of it.
- So, do they go with 36 CUs? Or 72 CUs? 36 is probably the more practical choice.
The result is that as they got closer to RDNA 2 (and thus the SOC) becoming a physical reality, the speed of the SOC maybe have increased over time due to RDNA 2 being more efficient than expected. So, it's possible that it started with a target of 9.2 GHz due to what they expected to be their max clock prior to silicon taping out. As AMD has done testing on it, they've been able to boost the clocks to where it is now.
This may be why we still haven't been shown the retail case for the PS5. I get the feeling that because MS started off not knowing (but expecting really high) what their power consumption would be or how hot their 12 Tflop SOC would be that they designed a robust case that would deal with a worst case scenario. IE - I get the feeling the case was designed before they had an SOC.
I get the feeling that the cooling for the PS5 may be more exotic and/or complex than the XBSX, so Sony's designers may still be looking at how they can make an attractive/striking case compared to MS which went with a more industrial/living room look. Cooling a narrow 2+ GHz chip is likely not trivial. The chip itself is going to have less surface area and 2.23 GHz may be beyond the power efficiency elbow of the power curve.
All that said, it's good that the boost is wattage limited and not thermally limited. However, high thermals can affect power consumption, so the thermal solution will have to keep the chip below X temperature at all times in all environments to ensure that the chip can always hit the expected clocks at the given power target.
That said, this does bring up some things that developers will have to keep in mind with PS5 performance that they don't have to with XBSX performance.
- If you have code that pushes the CPU and GPU equally hard, neither the CPU nor GPU will hit the boost clocks during that time.
- Most of the time this shouldn't happen however, so the variable frequency shouldn't hurt it much.
- If Sony allows the use of SMT, the GPU may be negatively impacted.
- The purpose of SMT is to allow fuller use of the CPU by allowing more threads to run on a CPU core to take advantage of when the core would be idle.
- Basically by increasing occupancy on a CPU core, the CPU core will be idle less often, hence the CPU core will use more of the power budget at any given time.
- This means that the CPU will be in contention with the GPU for the power budget far more with SMT than without.
- IMO, because of the variable frequency of the CPU and GPU, I don't think Sony will expose SMT to developers.
I'm really excited that Sony focused as much as they did on Audio, I REALLY hope that audio takes off this generation, but a lot is going to depend on just how robust Microsoft's "3D audio hardware" is. If it ends up only being 1st party developers taking advantage, that's cool, but doesn't move the gaming landscape. I want the gaming landscape to get moved WRT to not just audio positioning but audio processing.
Regards,
SB