RussianSensation
Elite Member
- Sep 5, 2003
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Why is everybody assuming this is polaris on 14nm?
Simply put, a cut down 2304 Hawaii doesn't make sense from any angle and AMD has no other design on 28nm that can fit 2304 shader description with 256-bit bus, and still manage to meet the die size/power usage/cost characteristics.
3 reasons 14nm Polaris 10 makes the most sense:
1) No single GCN 1.0/1.1/1.2 GPU has a UVD block inside that supports HDMI 2.0 4K output. AMD stated themselves that the lack of HDMI 2.0 functionality cannot simply be added to Tahiti, Tonga, Hawaii or Fiji without an ASIC redesign. Last time I checked DisplayPort 1.2 wasn't widely available on most 4K TVs.
2) Die size and cost
Think about how large the current PS4 APU is. If you were to take a 2048 Tonga 365mm2 (?), it grows even more. Yet, the specs call for 2304 part so it has to be a cut-down Hawaii? But then the memory bandwidth with those GDDR5 speeds don't add up. It means you'd have to cripple its 512-bit bus in half. This would be the most inefficient design, with massive die size and still too much power usage. 14nm Polaris 256-bit solves the die size and power usage scenarios. Think about 14nm vs. 28nm. Polaris 10 brings 2-2.5X perf/watt but a shrink alone doesn't even get Sony to 2X. This once again would make shrinking old designs not as perf/watt efficient which is critical for a small console enclosure.
3) Cost. A redesigned for 14nm Polaris 256-bit is more cost effective since it was designed form the ground up for this node, and by itself is more power effecient. If would be too risky and more inefficient/costly to shrink old Hawaii to get 2304 R9 390 on 14nm. Might as well take the latest tech optimized for 14nm -- that's Polaris 10. Since AMD was already making 14nm Polaris 10 for PCs, they would eat the cost of a die shrink, NOT Sony. That means Sony wouldn't be thrilled to pay extra to shrink old Tonga/Hawaii when AMD had off the shelf Polaris 10 ready to go.
Sony also gets even better backward compatibility since GCN 4.0 would be even closer to the architecture likely found in PS5 (2019-2020). If they price this at $399, and drop the base PS4 1152 shader model to $299, many people will easily spend $100 more for a PS4K. This console could also ship standard with a 1TB HDD, and have higher trade-in value when PS5 launches. If Sony launches it at $499 though and barely drops PS4 to $329, well then it might not be that successful .
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