q264 High Profile Quality Variation
(Click thumbnails to open the full-size images.)
These show the PSNR of q264 High profile across the three test machines. These show the relationship of the different speed-quality settings so that future charts can use only one of the settings to avoid clutter. For q264, speed-quality (usage) value 4 looks like a reasonable choice to represent the overall PSNR.
One of the main questions to answer is how does Haswell's HD Graphics 4600 quality compare to the prior generations.
These compare the PSNR between the different CPUs at speed-quality setting 4 (the middle one). Haswell's Baseline profile quality at setting 4 is essentially the same quality as Ivy's. More importantly, Intel's newer Haswell architecture shows a relatively large increase in encoded video quality for the Main and High profiles.
These compare the speed between the different CPUs at speed-quality setting 4 (the middle one).
Surprisingly, for the Baseline profile has1 is slower than both ivy1 and sb1. Perhaps Intel has de-emphasized the Baseline profile in their design due to its relatively lower importance to customers. It may be that relatively few customers are using Baseline because even mobile devices support the more complex profiles.
Beyond the Baseline profile, it looks like Haswell's HD 4600 sacrifices some speed to get the increase in quality over Ivy Bridge's HD 4000. Note that that ivy1 has a 3.5 GHz base clock and has1 has a 3.4 GHz base clock. That accounts for some of the drop, but not much.
Given that Quick Sync is very fast but has typically been lower quality this speed sacrifice for higher quality makes sense. And in fact it would have been nice to push this trade-off even further at the higher quality settings given that the user can choose the speed-quality setting that suits them.
HD 4000 (Ivy) vs HD 4600 (Haswell): High Profile Quality and Speed Spreads
These somewhat cluttered charts compare the speed and quality of encoding between the Ivy Bridge and Haswell chips at various speed-quality settings for the High and Main profiles. Haswell has Ivy well covered in the PSNR domain; even the fastest Haswell encode is higher quality than the highest quality Ivy Bridge encode.
The speed charts show that Haswell covers a much wider range of speeds, with that range centered slower than Ivy.