The M6 iMac is here to replace the M4 iMac. This time Apple didn’t raise prices at launch, but that’s only because prices already went up earlier this year. If you already have an M4 iMac, should you upgrade to the base M6 iMac for $1,499 or the un-neutered M6 iMac for $1699? Or if you’re planning to buy an iMac, should you go for an M4 model while you still can (new, clearance, or used) to save a few hundred dollars? And what are all the differences between them? Let’s find out.
Outside
On the outside, nothing has changed from the last generation. It’s the same 24-inch design and the same colors, so let’s move to the inside.
M6 vs M4 Chips
Now let’s talk about the biggest difference: the chip. Like before, there are two tiers of iMac, one with 2 Thunderbolt ports starting at $1500 which I’ll call the two-port iMac, and one with 4 Thunderbolt ports starting at $200 more, or $1700, which I’ll call the four-port iMac.
The base two-port iMac now has an M6 chip with a 10-core CPU, made up of 2 super, 3 performance, and 5 efficiency cores. This is 2 cores less than the Mac mini’s M6 chip, but it’s up from the 8-core CPU in the base M4 iMac, which had 4 performance and 4 efficiency cores.
Interestingly, that means the base M6 actually has one fewer “performance” core than the M4. But it gains 2 super cores, which sit above performance cores, plus one extra efficiency core, so it will still come out well ahead. The GPU goes from 8 cores to 10 (or 25% more cores). More on performance in a bit.
The four-port iMac gets the full M6 chip with a 12-core CPU: 2 super, 4 performance, and 6 efficiency cores. That compares to the 10-core M4 with 4 performance and 6 efficiency cores. The GPU goes from 10 cores to 12, which is 20% more cores.
The 12-core M6 is the same chip as in the M6 Mac mini, and it’s two generations newer than M4. That means we can expect around 22-27% faster single-core performance and around 33-40% faster multi-core performance on the four-port model. Since the base M4 iMac only had 8 cores, the multi-core jump on the base model could be even bigger, but benchmarks will tell.
On the graphics side, there are 2 generations’ worth of GPU upgrades. Those include updated Dynamic Caching, improved ray tracing, and a Neural Accelerator in every GPU core for better AI performance. Apple says to expect up to 2 times faster graphics than the M4 iMac.
Speaking of AI, both M6 iMacs have TWO 16-core Neural Engines, compared to the single 16-core Neural Engine in the M4. Apple says to expect up to 5 times the on-device AI performance of the M4 iMac.
Memory and Storage
Now let’s get into the biggest money pit these days: memory and storage. Unfortunately, even though prices have increased, you don’t get any more memory or storage for it: both M6 iMac models still start at 16 GB and 256 GB, just like the M4 iMacs did.
Memory limits are also unchanged. The base two-port iMac can only go up to 24 GB for $200 extra, which is Apple’s standard charge of $25 per gigatbyte. The four-port iMac offers the same upgrade to 24 GB, or you can go up to 32 GB for $400 extra, again the same $25 per gigabyte.
There are speed improvements, though. The M4 iMac’s memory bandwidth was 120 GB/s regardless of size. Apple’s spec sheet for the M6 iMac only says “up to 170 GB/s,” and from what’s been reported, the 16 GB configuration gets 153 GB/s, a 28% boost. You’ll need to upgrade to 24 or 32 GB to get the full 170 GB/s, which is 42% faster.
For storage, the two-port iMac goes from 256 GB up to 1 TB, and the four-port model goes up to 2 TB, the same as the M4 generation. Upgrade pricing matches the M6 Mac mini, and it’s still expensive:
- 512 GB costs $200 more, which is a whopping $800 per terabyte.
- 1 TB costs $500 more, or $667 per terabyte.
- 2 TB costs $1,000 more, or $571 per terabyte.
The good news is that Apple says the M6 iMac’s storage is up to 2 times faster for reads and writes than the M4’s, thanks to PCIe 5.0 support. Like with the Mac mini, it’s uncertain exactly what this means for the base 256 GB models. In the past, lower-capacity models have sometimes had half the speed of higher-capacity ones because they use fewer NAND chips. I’m not sure if speeds have doubled across the board, or if the gap between lower and higher capacities has just narrowed. I guess benchmarks will tell.
Connectivity and Ports
Another big improvement on the M6 iMac is connectivity, both wireless and wired.
For wireless, the M6 iMac now has Apple’s N1 networking chip, which means Wi-Fi 7, Bluetooth 6, and Thread networking support. That’s compared to the M4 iMac’s Wi-Fi 6E, Bluetooth 5.3, and no Thread.
On the wired front, the iMac’s Ethernet port is still built into the power adapter rather than the computer itself. But it’s now 2.5 Gigabit instead of 1 Gigabit. The base two-port model doesn’t doesn’t include it automatically; it’s an optional $30 add-on. The four-port model does have it included in the price already.
The rest of the ports are the same. The two-port iMac has two Thunderbolt / USB 4 ports, and the four-port model has four Thunderbolt 4 ports, all up to 40 Gb/s. And both still have a 3.5 mm headphone jack with support for high-impedance headphones.
Displays
Now let’s talk about displays. Firstly, the built-in display hasn’t really changed between M4 and M6 iMacs, but Apple does have a big “LED” icon listed on the M6 models, whereas it’s not there on the M4 models. I don’t think this indicates an actual difference, but rather this is because they released new Tandem OLED MacBook Pros, which have this other icon, so they started adding these new icons, including “Mini-LED” for the non OLED MacBook Pro, to help differentiate, but they just haven’t bothered going back to all the older products to add an icon for them.
For external displays, there is again what I believe to be mostly a labeling difference. The base two-port M6 iMac supports one external display at up to 6K at 60Hz or 4K at 165 Hz. The base M4 iMac only lists the “up to 6K at 60 Hz” part, leaving out any mention of 4K. However, I don’t there is actually a capability difference here, just that Apple is trying to be more thorough now in their documentation.
Similarly, the four-port M6 iMac can drive two external displays at up to 6K at 60Hz or 4K at 165Hz each. Or it can drive one display at up to 8K at 60Hz, 5K at 120Hz, or 4K at 240Hz. The four-port M4 iMac only lists the top resolutions and foregoes the rest, but there shouldn’t be any difference.
Summary: M6 vs M4 iMac
Alright, let’s summarize the differences. The M4 iMac launched at $1,300 and $1,500 for the two- and four-port models, then rose to $1,500 and $1,700 in June. Those are now the starting prices for the M6 iMacs. If you’re buying new at Apple’s current prices, here’s what you get for the exact same money:
- The M6 chip instead of the M4 chip, with 2 extra and faster CPU and GPU cores that are 2 generations newer. The M6 also has a DUAL 16-core Neural Engine. That’s around 22-27% more single-core and roughly 33-40% more multi-core performance on the four-port model, possibly more on the base model. According to Apple, you also get up to 2 times the graphics performance and up to 5 times the AI performance.
- 28-42% faster memory bandwidth of 153 or 170 GB/s, depending on capacity, compared to 120 GB/s.
- Potentially twice the storage speed.
- Wi-Fi 7, Bluetooth 6, and Thread networking support, compared to Wi-Fi 6E, Bluetooth 5.3, and no Thread.
- And a 2.5 Gigabit Ethernet port on the power adapter instead of 1 Gigabit.
- And possibly slight faster refresh rates when using the max number of 4K external displays
The new M6 iMac provides a sizeable speed increase everywhere from the chip to memory to storage, and even networking speeds. If you’re wondering whether to spend the extra $200 on the four-port iMac over the two-port, I’d say it’s definitely a good deal. After all, part of that money is the $30 for the 2.5 Gigabit Ethernet port, 2 extra Thunderbolt ports, and 2 extra or 20% more CPU and GPU cores, as well as Touch ID on the keyboard without number pad. If you allocate either $100 or $150 for the better chip, that’s still only a 7-10% price increase for 20% faster speed.
And if you’re wondering whether the M6 iMac is worth $200 more than the M4 iMac’s original starting price before the hikes, I would say the speed increases make it a worthwhile update, especially if you use AI.
But soon, clearance and used M4 iMacs may be flooding the market, and that’s an opportunity if you can snag one at a discount. How much of a discount? Well, consider that the CPU speed difference is around 33-40% and the GPU is 2 times or more. If you’re mainly concerned with CPU performance, I’d say around $1,100 or less for a four-port 10-core CPU M4 iMac, or around $1,000 or less for the two-port 8-core CPU model, could be a decent deal. That’s a few hundred dollars below what the M4 iMac cost at launch, before the memory crisis.
If you have a use for the GPU and AI improvements, however, you’d probably need to find a four-port M4 iMac around $850 or so to make it a reasonable alternative, which I think won’t happen for a long time.
As for current M4 iMac owners, unless you need the extra performance or faster networking, there isn’t much reason to upgrade. It’s the same screen, same camera, same speakers, and same design.
In conclusion, if you are buying new, the M6 iMac is still a “good” deal, especially since it costs the same as the M4 it replaces.
