Apple’s 2021 MacBook Pro models have cemented themselves as absolute workhorses, with publications like The Verge calling them “the most powerful laptops” ever in their reviews.
The 2021 MacBook Pro can be had in a 14″ or 16″ chassis, with a choice between Apple’s new M1 Pro and the higher-end M1 Max chips.
The latest MacBook Pro is equipped with what Apple calls ‘Unified Memory’ — a single pool of RAM shared by both the CPU and GPU. The M1 Pro can be outfitted with either 16GB or 32GB of the stuff, while the M1 Max can be configured with either 32GB or 64GB of Unified Memory.
While the M1 Pro’s memory bandwidth caps out at 200GB/s (which is still double that of the base M1), the M1 Max manages a whopping 400GB/s.
We’ve already seen how impressive the 2021 MacBook Pro is in RAM-intensive tasks and memory management, but how does all of that memory magic translate to everyday use, say, for your average Tim who gets most of his work done on Chrome?
MacRumors Forums member yurkennis, an avid Chrome user who daily drives dozens of tabs, set out to determine exactly that through a detailed experiment which, admittedly, “is over-stretching for a regular browser user.”
The forum user’s methodology was pretty simple — they opened multiple, non-overlapping Chrome windows (all in the foreground and actively displayed on the same screen), opened dozens of tabs in each instance, used the Revolver Chrome Extension to make each window switch tabs every second, and kept constant track of memory usage, swap usage, memory pressure, and system responsiveness as the experiment progressed.
Take a look at yurkennis‘s findings for the M1 Pro, equipped with 32GB of Unified Memory:
- At 3 windows totalling 379 tabs, all of them are shown immediately after switch, system fully responsive, memory pressure is mostly green with occasional yellow
- 4 windows (407 tabs): memory pressure is always yellow;
- 5 windows (447 tabs): system becomes less responsive while new tabs are opened
- 6 windows (469 tabs): each tab appears with a fraction-of-second delay after switch, looks like it is read from swap most of the time
- 7 windows (514 tabs): on most of switches, 1-2 tabs appear blank as if SSD swap starts becoming a bottleneck
- 9 windows (608 tabs): on most of switches, 3-5 tabs appear blank; closing any single Chrome window takes 15-20 seconds
- 10 windows (641 tabs): 50%-70% of tabs appear blank after each switch, even after 30 minutes of stabilisation (SSD swap seems a real bottleneck now). Memory pressure becomes occasionally red. CPU cores are used around 90%, fans run at 2300-2700 rpm; total power reaches 48W. Opening the last 30 tabs takes 55 seconds (vs 5 seconds on 64GB Max). Clicking system menu takes few seconds for iStat icons. Looks like the system is completely busy with retrieving tabs from swap and displaying them, in a loop.
yurkennis concluded that the M1 Pro with 32GB of Unified Memory can easily handle around 380 Chrome tabs without even breaking a sweat, and it isn’t until you go up to around 350 tabs that system performance and responsiveness start taking a hit.
As expected, the M1 Max with 64GB of Unified Memory (and double the M1 Pro’s memory bandwidth) performed even better.
“64GB remains absolutely fluid up to 640 tabs (and will likely sustain several 100s more),” said the forum member. It looks like the legendary memory hog has finally met its match.
“In all cases, 64GB Max switches all tabs absolutely instantaneously. For 10 windows (641 tabs) open on Max, CPUs are used at 50%, Fans: 1500-1600 rpm; total power: 20W.”