There are a few. They are able to do this by using something called Display Stream Compression. While it may be find for some, a lot of us would prefer not to have a diminished experience with a compressed stream.
Display Stream Compression (DSC) is fine. It is not a "diminished experience". DSC is visually lossless.
Instead, those docks use a technology called DisplayLink which has nothing to do with DSC. DisplayLink means that external monitors are basically "software" displays that are tremendously slower and often very limited in resolutions and frame rates. Having any DisplayLink display connected also breaks HDCP and can cause other problems.
"Marketing lies" is unnecessarily inflammatory. I googled before posting to see if I could find anyone legitimately complaining about DSC, and it really seemed like pretty much everyone was happy with it.
There are always people like "audiophiles" who claim to be able to distinguish impossibly small differences, and there is perhaps a very small number of people with exceptional hearing who actually do... but 320kbps compressed audio is "audibly lossless" for most of the population. The exact same thing applies here, by all appearances. I'm sure there are mp3 test cases where the compression does something terrible, just like with DSC... that just isn't what people actually encounter day to day.
I can't see the second study linked which is on IEEE, but if you look at the fist one, Figure 4 shows that DSC was "visually lossless" in almost all test cases. Let me quote one thing from that study:
> As described above, the HDR content was selected to challenge the codecs, in spite of this both DSC 1.2a and VDC-M performed very well. This finding is consistent with previous series of experiments using SDR images.
So, this testing was done with samples that would challenge the codecs... and they still did great. It doesn't appear to be "marketing lies" at all. It appears to be a genuine attempt to describe a technology that enables new capabilities while dealing with the imperfect limitation in bandwidth of the available hardware.
Do you have some terrible personal experience with DSC to share? Did you do a blind test so that you weren't aware of whether DSC was enabled or not when making your judgments? Are you aware that almost all non-OLED monitors (especially high refresh rate) always have artifacts around motion, even without DSC?
I haven't personally had a chance to test out DSC other than perhaps some short experiences, which is why I based my initial comment on googling what other people experienced and how Wikipedia describes it. You pointed me to a study which seems to confirm that DSC is perfectly fine.
Common sense suggests that "visually lossless" means no detectable difference by the naked eye ever, not in "almost all test cases". MP3 is a very old codec, and it's possible that there are still some "killer samples" that can be ABXed by skilled listeners with good equipment even when encoded by a modern version of LAME. A better example of something that could reasonably called "audibly lossless" might be something like Opus at 160kbps, for which I've seen no evidence of any successful ABX. But even that is is usually called "transparent", not "audibly lossless", so not only is "visually lossless" a lie, the name itself is propaganda.
DSC doesn't solve the hardware limitation of only being able to drive a single external display on the M1, that's a hardware thing that cannot be changed. You have confused it with DisplayLink, which is basically another graphics card, hence why it "solves" this problem, but the experience is worse because it's CPU-intensive/software rendered.
I bought and followed the online tutorials about using the DisplayLink docks and whatever else I purchased from Amazon and I couldn't get it to work with 2 external monitors. It isn't straightforward.
My 13" 2014 MBP supports 2 mDP + 1 HDMI = total 3 external displays.
Running external display at 4k@60Hz is possible but not straight forward, it requires patch core graphic framework, or using 3rd party boot loader. Newer models do not have this limitation afaik.
[0]: the exception is the M1 Mac Mini, which doesn't have an internal display, so it can use two external displays.
[1]: once again, the desktop version without a built-in monitor can support one additional monitor, so the Mac Studio with M1 Max can support 5 displays.
Every GPU on the market supports a limited number of monitors. There are fixed-function (not programmable in a traditional sense) blocks of silicon that are used to support each monitor.
M1’s GPU came equipped to only support the internal monitor and one external monitor… a very slim configuration, but that’s likely influenced by its smartphone processor ancestry. Smartphones don’t need to power a bunch of displays.
The larger M1 chips have bigger GPUs with more of those fixed function blocks.
It isn’t artificial market segmentation at a software level, but it is certainly market segmentation at a hardware level, and something they knew would happen when they designed these chips.
In the end, they were pretty spot on about the market segments. Most people want/need external display support… but one external display is plenty for most people. People who need more are likely to also want more in general, and the higher end options satisfy that.
It still would have been nice for them to upgrade things for M2.
> People who need more are likely to also want more in general, and the higher end options satisfy that.
I disagree. The topic comes up repeatedly whenever Apple Silicon is discussed. It’s my impression that for quite a lot of us the base M1 or M2 would be everything we wish for from a pure performance perspective. Yet the limited display output options are the only thing that force us towards the Pro and higher tiers.
It seems like a deliberate limitation and I don’t like this form of product segmentation.
I agree that they were pretty spot on with the market segmentation. I’m one of the folks who doesn’t need more than a single external monitor, and I consider myself a power user when it comes to resource consumption. I just wish the cost of ram would come down, holy moly.