If you want to complain how slow your 4.5 year old Macbook is compared to 2015 Laptop, find another forum. Or a doctor

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5 Hours on internet browsing is about half of what you can do on 2015 MBP. Sorry, but laptop is meant to be portable computer, not a brick that you have to plug into the wall to actually use it.
If you want a gaming machine buy a desktop.
End the discussion about how awful in gaming are Apple computers. Its thread about APIs on OSX. Discussion about gaming market as a whole is also IMO allowed here.
Leman, actually there is a lot of competitive gamers. 25 mln of accounts in League of Legends are active accounts. 10 mln of WoW, 5 mln in Starcraft, 8 mln in Diablo 3, 8 mln in Heroes of the Storm, 20 mln in Hearthstone, if we think about whole gaming market on PCs. and a there will be a lot more. People dont realize how big market is Multiplayer market in gaming. I would say that its over 80% of whole market as of right now.
And in future it will be a lot more than that.
I can't help but facepalm at this. I wasn't complaining how slow my 4.5 year old laptop was compared to a new laptop. That would be insanely daft. I was complaining that the new laptops are still as slow as the 4.5 year old laptop. Got it? Not difficult.
If you want 10 hours of battery life in your machine, that's fantastic - and I fully support your decision to have that kind of power efficiency. It's great. But there are a lot of customers out there who just aren't satisfied with the kind of performance you get out of that, and those are now being completely left out by Apple.
Not everyone wants to game only on desktops. Some of us actually have work and travel a lot, and we like to get our game on in long train trips and stuff like that. With the current line-up, that simply isn't available to us. Transporting your entire desktop is quite difficult and isn't viable, so desktops aren't viable for gamers on the go. Trust me, I know - I go to DreamHack every year and every year it's a pain to transport my PC up there. It's worth it in that particular case, but really...
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Guys, I really don't want to appear needlessly confrontational, but it seems that our definition of 'competitive gaming' differs. I don't see a casual WoW/DOTA2/HT/SC2 player as a competitive gamer. By your definition I am a competitive gamer as well

Maybe a different term like (semi)pro-gamer would be more accurate. At any rate, my previous point is still in effect — people playing all these multiplayer games casually are absolutely fine with current Mac hardware. All these games will run on integrated GPUs that are in the modern Mac lineup (maybe by exception of the new MB).
You are a competitive gamer indeed. How could you not consider WoW, DotA2, HotS, and SC2 competitive games? That's hilarious!
Competitive gamer != Professional gamer.
DSA and much of the DX emulation stuff became core in 4.5, so I thought you are referring to that. I am not sure what DX calls you are talking about in 4.4, but anyway, that doesn't matter.
No - it actually became core in 4.4. Look it up. Anyway, doesn't matter at this point. I'm sure that if Apple decides to fix OpenGL, then they'll put in 4.4 and 4.5 at the same time anyway.
The extensions you talk about do not really 'skip' frames, they just stall the presentation (block the rendering thread) until a particular event (number of refresh rates) fires. What you wrote sounded to me like they would cause OpenGL to abort its current rendering. Sorry if I misunderstood you. Anyway, kCGLCPSwapInterval is supposed to do exactly the same.
But what you describe is basically exactly what skipping frames is. The rendering thread is behind the presentation interval, so we skip a (few) frame(s) to catch back up.
However, this whole thing of "when you're behind" can be implemented in quite a few different ways.
Precisely what the difference between the Apple and non-Apple implementations are I do not know, but it's VERY obvious when you actually play games on a Mac with V-Sync on. You really owe it to yourself to try. It's rather painful actually.
Of course all of this would be solved if Apple implemented freesync/g-sync into their machines... which they totally should! That would be very, very awesome and would be exactly the kind of thing you'd expect from Apple: Presentation is important! Get a picture-perfect and beautiful desktop.
Anyhow, getting back to Metal... I wouldn't expect Metal on desktops. Metal was very specifically built with their own mobile chipsets in mind. However, I do think they'll suppoort Vulkan, which is a lot like Metal actually. I think we'll see Vulkan on the Mac and DX12 on Windows.