Hey,

well, my parents are thinking about buying new iMacs, now I wonder about installing Windows for some games. Does this make sense? Are they nearly as fast as PCs similarly configured, or much slower?

Greetings,
Pete

[P]

If you're running in Bootcamp, they're exactly as fast as a similarly specced PC, and much faster at gaming than when gaming in OS X. Note that the GPUs in iMacs rate mobile GPUs, so they're not comparable to desktop cards by similar names.

[BLAZE_MkIV]

Game developers, video card manufactures and Microsoft optimize the PC platform for gaming performance. Apple has consistently ignored the gaming market entirely. Even though games were the iPhones killer app.

Originally Posted by P 

If you're running in Bootcamp, they're exactly as fast as a similarly specced PC, and much faster at gaming than when gaming in OS X. Note that the GPUs in iMacs rate mobile GPUs, so they're not comparable to desktop cards by similar names.

What does this mean? This is really mobile discrete graphics hardware? I always thought the iMacs graphics were so fast, really...

[P]

There is a standard for discrete mobile graphics cards called MXM, which is basically PCIe plus an internal display connection (eDP or LVDS). Apple buys such cards on the market and install them into the iMac and the 15" MBP - the only special thing about them is firmware. The highest spec MXM cards are rated at 100W, which is nothing compared to what desktops use (although strictly speaking nVidia is cheating with this limit, exceeding it with the 680MX and the 780M). Both nVidia and AMD make mobile cards optimized for lower-power usage, but even so, their top cards are usually not released in a mobile version. To justify OEMs charging through the nose for these GPUs, nVidia began maintaining a separate numbering system for the mobile chips, and AMD eventually followed suit (from the 5000 generation).

This put Apple in a bind. For the longest time, Apple tried to translate the mobile chips they used in their iMacs back to the closest desktop equivalent (e.g. the 5750 in the 2010 model was actually a 5850M, IIRC), but in 2011, they finally gave up and just started advertising the mobile graphics model numbers. Right now, Apple uses Iris Pro 5200 (same as the mobile model), 750M (essentially a desktop GT 640), 755M (desktop GTX 650), 775M (desktop 670 underclocked to be weaker than a 660 Ti) and 780M (desktop 770 underclocked to something similar to a 760). The last two cards are good gamer cards that can actually handle the native res of the 27" iMac, but they are sold in the top crazy-expensive model. The two 21" models use weaker cards designed for a lower res, and the bottom 27" is not much better. The cards we're missing are the 760M-770M, which would do a good job in the 21" models, but unfortunately Apple is not offering them as an option.

Hey,

ah, don't get me wrong, but I didn't understand most of this :-) (thx though).

How fast are they, really? Why would they do this, using mobile chips, power or heat or both? I thought pricing was usually identical.

I really think finally making a decision and getting the bigger 21.5" iMac model would be a good idea. I just really wanted a retina display... But I love the big screen! I'm on notebooks and tablets forever, but this... Oi.

I would only use Windows for games, hmm.

Technically, though, why isn't it the other way around, really. Look, Carmack said games were twice as fast on PS4 than on a similar PC, at least after some time, iPads are only possible because iOS is so neatly integrated. There are not SO many Mac configurations and with a company as powerful and rich as Apple couldn't they reach much better speeds through tighter integration?

Hmm,
Pete

[P]

Originally Posted by PeterParker 

Hey,

ah, don't get me wrong, but I didn't understand most of this :-) (thx though).

How fast are they, really?

Pick the model you're interested in. Check which desktop card it corresponds to in my post above. Google that card and "review" or "benchmark". That's how fast it is in Windows.

Originally Posted by PeterParker 

Why would they do this, using mobile chips, power or heat or both? I thought pricing was usually identical.

Pricing is far from identical - the mobile chips are expensive. Apple use them mostly for heat, but also because it lets them offer BTO options. They can't fit an entire PCIe card inside the iMac, and even if they could, they'd have to hack something up for the connector, since it is a DP/DVI/HDMI rather than the internal eDP/LVDS. Back when the options were DVI or LVDS, this was very hard - today, it's DP to eDP which is doable, but they still can't fit the card physically.

No, what they do is that they buy standard PC MXM cards, load them up with a special firmware if required, and install them in a standard slot in the iMac. If you want a better GPU, they can easily switch in a different one at BTO. It would be possibly to sell these cards aftermarket, and attempts have been made, but the market is just too small to bother with.

What they COULD do is what they did on the new Mac Pro: Buy the desktop chips (just like Sapphire and Asus and XFX and whatnot do when building GPUs), buy GDDR5 memory, and design a new GPU onto the iMac motherboard. That has problems, however: They'd have to redesign the motherboard every time, because both the GPUs and Intel's CPUs switch sockets, they can't offer so many GPU options, and they still have the cooling problem. For now they stick with the mobile chips and pay the premium.

Originally Posted by PeterParker 

I really think finally making a decision and getting the bigger 21.5" iMac model would be a good idea.

21.5" is the small one (1920*1080). The big one is 27" (2560*1440).

Originally Posted by PeterParker 

Technically, though, why isn't it the other way around, really. Look, Carmack said games were twice as fast on PS4 than on a similar PC, at least after some time, iPads are only possible because iOS is so neatly integrated. There are not SO many Mac configurations and with a company as powerful and rich as Apple couldn't they reach much better speeds through tighter integration?

Many reasons.

1) The market for PS4 games is much bigger. Sony puts more work on the drivers, game developers spend more time optimizing. Apple barely cares about games at all.
2) Apple uses only a high-level API (OpenGL) while the PS4 also offers a low-level API with much less overhead. The downside with the low-level is that you have to develop for a specific GPU. That's not a problem for a console that stays constant year after year, but Apple makes new Macs every year.

Aha, aha, hmm...

Bigger model to me was the faster 21.5 iMac, as there are two models offered. So this one has a real "mobile" graphics card, apparently, not only the Iris Intel one. How fast is it, the graphics on my bigger model? How about the whole debate on in how far applicatins are actually graphics card-optimized? I mean... I used to think the whole OS would rely so much on graphics stuff it would use the GPU as much as possible. Apparently, this is not true. A MBA often seems not so slow in everyday stuff, even lots of Photoshop work. You notice the difference in games, but other than that?

To be honest, I don't understand all of this, really. Look.
a) Why are they using mobile chips instead of normal ones? Because of the whole socket/motherboard redesign thing, apparently, right? So I thought it would rather be about heat, power and price. Price no, they are expensive, right. Power and heat, well, if they are mobile chips, I suppose there we go they don't consume so much power. Is that so important with a desktop? I mean, do computers need so much power after all? If they reduce 30%, and it's no problem anyway, who cares. So the socket thing, alright. (Btw, why can a company as rich and as powerful as Apple not afford to handle the socket thing alrigt and simply use a real GPU? Careless?)
b) What I was trying to say on consoles and iOS was not only about games. I thought it was the extreme level of integration that makes iOS so fast - or at all possible - after all, no? I mean, there are always really only three or four iPad models supported, right? So you can optimize for the few models you support. I wonder, is OS X really optimized for hardware? Apple never went this way, I think, for the advantage of using really any kind of hardware, vendor etc. It would make sense, sort of. If there are always only 50-60 Mac models supported by an OS X version, you could optimize more deeply. On the other hand, Apple knows the hardware in the iDevices really well, and maybe they just don't "get to know" their GPUs well enough before deciding to switch vendors all over. Hmm. Just thinking.
c) This post was more about the question if it makes any sense to install Windows on a new Mac, I mean... You don't configure it so sensitively, right, you simply go for a general workeable environment. Each time you go back to use an app or play a game, first you have to run your regular updates, of which, everyone knows, there are rather many on Windows... What I meant with the "how fast" question is, if there are any windows benchmarks of various apps for Mac models, I looked and didn't find anything so quickly.

Greetings,
Pete

[ghporter]

For one thing, Apple uses mobile components because they're smaller and allow for more compact products, mobile or desktop.

Without having actually run any real benchmarks, I can tell you that my 2006-vintage MBP runs Windows 7 at least as fast (from a user experience perspective) as a fairly well equipped desktop PC. I've built many a desktop PC, and so far my (now slightly dated) Macs have always been more able with Windows than most PC desktops with all but the highest-end components.

As another data point, a friend has a slightly newer MacBook that he set up to dual-boot OS X and Windows XP. Running OS X and VirtualBox with a WinXP client was faster than booting XP. I've seen this on my iMac as well. If you set up the virtual machine with enough RAM, it can pretty well scream except in some areas. For example, it's not a gamer's solution.

Helpful?

[P]

Originally Posted by PeterParker 

Aha, aha, hmm...

Bigger model to me was the faster 21.5 iMac, as there are two models offered. So this one has a real "mobile" graphics card, apparently, not only the Iris Intel one. How fast is it, the graphics on my bigger model?

It's a 750M, which is roughly the same as a desktop 650. Desktop 650 is good enough to game at 1280*720 - i.e., 720p - with the pretties turned up, but not quite enough for the native 1920*1080p resolution. It's a rather minor update over the Iris Pro in the base model, to be honest, but the drivers are better - especially in Windows.

Originally Posted by PeterParker 

How about the whole debate on in how far applicatins are actually graphics card-optimized? I mean... I used to think the whole OS would rely so much on graphics stuff it would use the GPU as much as possible. Apparently, this is not true. A MBA often seems not so slow in everyday stuff, even lots of Photoshop work. You notice the difference in games, but other than that?

To be honest, I don't understand all of this, really. Look.
a) Why are they using mobile chips instead of normal ones? Because of the whole socket/motherboard redesign thing, apparently, right? So I thought it would rather be about heat, power and price. Price no, they are expensive, right. Power and heat, well, if they are mobile chips, I suppose there we go they don't consume so much power. Is that so important with a desktop? I mean, do computers need so much power after all? If they reduce 30%, and it's no problem anyway, who cares. So the socket thing, alright.

Well power is not really a big deal, but heat is. Depends a little bit what question you're asking here, but... The 750M in that case has a max TDP (=what the cooling system must be able to remove) of 50W while the desktop model I compared it with sits at 65W. By going to desktop chip, you have to cool away a third again as much heat and design your own GPU card - all to save the difference between the mobile chip and the desktop one. We don't know what the price difference is, but it would have to be rather big to make that worth it, and it can't be, given that nVidia sells those 750M chips in a lot of cheap laptops.

Move up the range a bit, and that TDP gap increases. The GTX 770M has a 75W TDP and is equivalent to a GTX 660 at 140W. The top 780M has a 122W TDP, with the desktop 770 that it is similar to using 230W. By comparison, the total DC output of the power supply currently in the 21.5 iMac is 186 W. Graphics cards are hungry beasts.

The alternative question is why Apple doesn't offer better graphics cards in their cheaper models. That is an excellent question - something like that 770M would let you game at 1080p without problems - but Apple doesn't offer it. It seems Apple just doesn't care about that market.

Originally Posted by PeterParker 

(Btw, why can a company as rich and as powerful as Apple not afford to handle the socket thing alrigt and simply use a real GPU? Careless?)

Apple is a for profit company. If they don't make money by doing that, they won't do it. Simple as that.

Originally Posted by PeterParker 

b) What I was trying to say on consoles and iOS was not only about games. I thought it was the extreme level of integration that makes iOS so fast - or at all possible - after all, no? I mean, there are always really only three or four iPad models supported, right? So you can optimize for the few models you support. I wonder, is OS X really optimized for hardware? Apple never went this way, I think, for the advantage of using really any kind of hardware, vendor etc. It would make sense, sort of. If there are always only 50-60 Mac models supported by an OS X version, you could optimize more deeply. On the other hand, Apple knows the hardware in the iDevices really well, and maybe they just don't "get to know" their GPUs well enough before deciding to switch vendors all over. Hmm. Just thinking.

Apple really doesn't care about GPU performance. They care about stability and correctness, which is why they make the drivers themselves, and performance is a distant second. They could easily get better performance by inviting AMD and nVidia in to do more of the driver work again. OpenGL is also rather heavy. Finally, the iOS hardware is not so shabby anymore. Those GPUs are reasonably powerful.

Originally Posted by PeterParker 

c) This post was more about the question if it makes any sense to install Windows on a new Mac, I mean... You don't configure it so sensitively, right, you simply go for a general workeable environment. Each time you go back to use an app or play a game, first you have to run your regular updates, of which, everyone knows, there are rather many on Windows... What I meant with the "how fast" question is, if there are any windows benchmarks of various apps for Mac models, I looked and didn't find anything so quickly.

I used to have Windows on this iMac for years (until I made a stupid mistake, and decided that I'd rather build a gaming PC than fix it) and it worked well enough. Performance is what you'd get on an equivalent PC, no big deal. That performance has been more than sufficient for years now, excluding gaming.