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I have a Mid 2012 MacBook Pro with a GT650M/Intel HD 4000 and a 2.3GHz i7 and a Late 2012 iMac with a GT675MX and a 3.2GHz i5, opening the applications folder in the dock and scrolling thru websites on chrome seems way laggier on my MacBook, i know its older but i didnt expect it to be that much laggier Both running Catalina 10.15.7
Hi Iv seen this happen a couple times when installing macOS Mojave and it’s usually fixed by reinstalling the OS however if this doesn’t work it may be something more hardware related I would also try closing all runnings apps and try a pram reset (here’s the guide)How to reset the SMC, PRAM and NVRAM on a Mac Laptop Hopefully this helps Thanks :-)
@danby ‒ I suspect your Mid 2012 Unibody MacBook Pro is still running with a HDD vs your Late 2012 Retina MacBook Pro which has a SSD. Spinning disk drives are slower than solid state drives! More so as the drive is used as unlike a SSD the files data blocks tend to get fragmented across the platters which causes the drive to work harder to find the fragments before it can show you what it is retrieving. A second factor is RAM, as you didn’t tell us what your systems have that too can effect things! In the case of the HDD system when you don’t have enough RAM it will leverage the drive for Virtual RAM so now that HDD fragmentation effects things here too! So running heavy RAM tasks (like web browsing) gets messed up to! To get better performance I would upgrade the HDD to a SSD as well as boost the RAM if you have anything less than 16GB. One warning here! The HD SATA cable should be replaced as well. The original cable was only rated to SATA II (3.0 Gb/s) data rate whereas your new SSD will push the cable much harder than what the old HDD did. You need to upgrade it to a SATA III (6.0 Gb/s) rated cable. To add to this the early versions of the better cable had some issues as such they too need to be replaced! If you don’t you’ll end up chasing your tail with performance issues which won’t make sense. As the data flow rises the flow will have CRC errors causing the retransmission of that given block stream. But it won’t be a one time even it will end up in a loop condition over and over again! Your system will heat up as the CPU is fighting it out with the drive where the middle man is the guilty party! MacBook Pro 15" Unibody (Mid 2012) Hard Drive Cable and the guide to put it in MacBook Pro 15" Unibody Mid 2012 Hard Drive/IR Sensor Cable Replacement Here’s a bit more on the failing cables Your Hard Drive Cable Is A Ticking Time Bomb
