AFAIK LR and ACR share the same code for the features they have in common. Then on top of that LR uses the Lua engine, and it would be interesting if and how well it can again take advantage of more powerful instructions when available.EdelweissPirate said:A quick Google search implies that Lightroom is only compiled against SSE2 and nothing later. On the other hand, I think the real question is: what instruction sets is ACR compiled against? I'd expect it's the same, but maybe others here have better information.
It looks some other Adobe products can use more advanced instruction sets, but those are the one more aimed at a more professional user, thereby less issue to increase the hardware requirements.
IMHO LR has room for big improvements, but the price may be to remove support for some older processors, and may require some deep code changes.