From AMD has told us so far, Polaris 10 is the mainstream GPU while Polaris 11 follows up as the budget card. Dubbed Ellesmere and Baffin respectively, they are part of AMD’s strategy to start off with small dies. Up until now, we’ve only had rumoured performance figures, with Ellesmere hovering about a 980Ti in performance. This all changes today with the latest rumours to come out.
Polaris 10 was previously expected to come in at 40CUs but the new report suggests 32CUs. Assuming AMD keeps the 64 stream processor counter per CU, this means a total core count of 2048, not 2560 as expected. At the same time, AMD has managed to squeeze out 5.5 TFLOPs, around the 5.9 TFLOPs offered by Hawaii. Given that theoretical TFLOPs is based on core count x core clock, this suggests a pretty high clockspeed for Polaris 10, likely around 1300-1400 Mhz. AMD has also managed to cut down power consumption to around 150W, with a 256bit bus of 8GB 7Gbps GDDR5.
Polaris 11 features a much lower CU count at 14, giving us about 896 stream processors. If we give the same clock speed boost as Ellesmere received, this would give us about R9 270/270X levels of performance, just ahead of the GTX 950. There will be 4GB of GDDR5 over a 128bit bus and 2.5TFLOPs of theoretical performance. Polaris also adds HVEC/H.265 hardware encode/decode acceleration, DisplayPort 1.3, and HDMI 2.0b outputs
The biggest question is how well these theoretical numbers map out to real world performance. AMD has done a lot of work to Polaris and GCN 4.0 so I expect that Ellesmere will surge ahead of the R9 380X clock for clock. Fiji had 8TFLOPs of theoretical performance but did not scale very well so there is definitely a lot of room for GCN 4.0 to improve on There’s also the question of overclocking as AMD seems to have gone a bit conservative with their clock speeds. Overall Polaris looks to be very promising and I can’t wait to see some cards!
Don’t forget that one source of these rumours – VC – says they are the mobile SKUs, not the desktop SKUs.