Why no HBM2 memory option on the top model 27" iMac?

[Ice Dragon]

I was a bit surprised. Might there be a reason for why this is the case?

 

[padams35]

GDDR6 is almost as fast, but cheaper and lower power than HBM2?

(Also Radeon's new Navi GPUs all use GDDR6 so Apple couldn't have included that without staying with an existing Vega card).

 

[Ice Dragon]

GDDR6 is almost as fast, but cheaper and lower power than HBM2?

(Also Radeon's new Navi GPUs all use GDDR6 so Apple couldn't have included that without staying with an existing Vega card).

Thank you. I thought HBM2 was better than GDDR6, but that makes sense.

 

[Zandros]

GDDR6 is almost as fast, but cheaper and lower power than HBM2?

(Also Radeon's new Navi GPUs all use GDDR6 so Apple couldn't have included that without staying with an existing Vega card).

No, HMB2 is expensive and lower power, which is why it makes sense in a limited power envelope (getting as much performance as possible in 50 W for the MacBook Pro 5600M). It would just cost extra money for little benefit in the iMac.

 

[pldelisle]

GDDR6 is almost as fast, but cheaper and lower power than HBM2?

(Also Radeon's new Navi GPUs all use GDDR6 so Apple couldn't have included that without staying with an existing Vega card).

HBM2 is on-package. It's cooler and uses less power than GDDR6. It's a lot faster (1.5-2x) but is extremely expansive.

 

[padams35]

No, HMB2 is expensive and lower power, which is why it makes sense in a limited power envelope (getting as much performance as possible in 50 W for the MacBook Pro 5600M). It would just cost extra money for little benefit in the iMac.

Thanks for the correction. I know the Vega cards were more power hungry than Navi, but it looks like I incorrectly attributed too much to the memory change vs miniaturization/architecture changes. (I also hadn't noticed Apple had customized their 5600M to use HBM2).

 

[Ice Dragon]

GDDR6 is almost as fast, but cheaper and lower power than HBM2?

(Also Radeon's new Navi GPUs all use GDDR6 so Apple couldn't have included that without staying with an existing Vega card).

Thank you. I thought HBM2 was better than GDDR6, but that makes sense.