Thank you for buying via links and ads on this site,
which earn me advertising fees or commissions.
As an Amazon Associate I earn from qualifying purchases.

Other World Computing...
B&H Photo...
As an Amazon Associate I earn from qualifying purchases.
Upgrade the memory of your 2018 Mac mini up to 64GB
Today’s Deal Zone Items... Handpicked deals...
$3498 $3498
SAVE $click

$3699 $1299
SAVE $2400

$1000 $700
SAVE $300

$3899 $1499
SAVE $2400

$748 $648
SAVE $100

$2999 $1999
SAVE $1000

$1699 $899
SAVE $800

$1698 $1398
SAVE $300

$4499 $3499
SAVE $1000

$1399 $1049
SAVE $350

$1149 $799
SAVE $350

$1399 $1049
SAVE $350

$1498 $1198
SAVE $300

$2797 $2597
SAVE $200

$280 $250
SAVE $30

$1699 $1299
SAVE $400

$8399 $7599
SAVE $800

$899 $799
SAVE $100

$1699 $1299
SAVE $400

2019 Mac Pro: Memory Bandwidth

2019 Mac Pro

MPG tested the $9399 Apple 2019 Mac Pro with 384GB OWC memory vs the top-end $3849 2019 iMac 5K 3.6 GHz Intel Core i9 8-core / Vega 48 with 128GB OWC memory. The memory difference is not a factor in this test.

The support of OWC / and B&H Photo is essential for making these reviews possible. Please order through our links via these companies and/or subscribe to diglloyd publications. Mac wish list • Storage wish list • SSD wish list • Ports wish list

Don’t overspend—not which Mac to get or how to configure it? Consult with Lloyd

This page uses the mt stress command of diglloydTools MemoryTester to evaluate available real-world memory bandwidth by a real application. Not to be confused with memory or CPU specifications—this is the real deal, what an application actually has available to it.

This test in effect forces the effects to be seen of both thermal throttling (extended intensive CPU usage), and the loss of Intel Turbo Boost (all CPU cores maxed-out). These figures represent what is possible with sustained memory access for 5+ minutes.

Memory bandwidth is especially important for more CPUs and/or fast ones because it can constrain how quickly data can be accessed by each CPU core. For example, the 2019 Mac Pro especially with 16/24/28 CPU cores needs all the bandwidth it can get.

Apple iPhone 7
Only $799 $295

MN9H2LL/A (USA/Global Unlocked)
Used, Mint Condition, Factory Unlocked

Does memory bandwidth matter for real world applications?

For memory intensive computations, memory bandwidth can have a measurable effect on performance. But many applications require only modest bandwidth, since a great deal of computation is done relative to memory access. And if disk I/o is involved then memory bandwidth falls by the wayside. So it all depends.

With only 8 CPU cores it is not likely to be an issue and not much with 12 cores. But starting at 16 cores, memory bandwidth is more and more of a factor (when all the cores are going full-tilt).

Results: Memory Bandwidth

Tested using the stress command of diglloydTools MemoryTester. See what a test run looks like.

The 2019 Mac Pro just stomps the 2019 iMac 5K for memory bandwidth. But note that the per-core memory bandwidth on the 8-core iMac 5K (16 virtual cores) is about 1.5GB.sec, whereas it is 2.5 GB/sec for the Mac Pro. This should not surprise, given 6-channel memory on the Mac Pro, versus 2-channel memory on the 2019 iMac 5K.

The more interesting 'find' here is that the Apple 48GB memory kit has about 1/3 less memory bandwidth than the OWC 6 X 32GB 192GB memory kit! Moreover, mixed sizes not matched up drop things even more (4 X 8 GB + 2 X 32GB). Anyone buying this class of machine would thus be well advised to pay attention to matched sets of memory, and not just any memory.

Why would you pay 2X to 3X as much for same amount of memory? Why would you buy a Mac Pro with overpriced and underperforming Apple 8GB modules?

2019 Mac Pro: memory bandwidth with various memory configurations

Why is OWC memory substantially faster than Apple?

One answer might be that the OWC 32GB modules have many more memory chips on each module, and that memory access could be interleaved (parallelized) within the chips on the module (???). It has to be something like that for a 33% faster throughput.

See the pictures below—the Apple 8GB RDIMM modules have about 1/4 the chips on them as do the OWC 32G RDIMM modules.

OWC 32GB RDIMM for 2019 Apple Mac Pro
Apple 8GB RDIMM for 2019 Apple Mac Pro
OWC Envoy Pro EX SSD
Blazingly fast Thunderbolt 3 SSD!

Up to 4TB capacity, USB-C compatible.

USB-C model also available

Great for travel or for desktop!
OWC Envoy Express

World’s first Thunderbolt 3 M.2 NVME SSD enclosure.

Super fast, bus-powered, 3.3 oz, DIY easy, rugged and compact!

See also OWC Express 4M2
√ No more slow and noisy hard drives!
OWC Accelsior 4M2 PCIe SSD
6000 MB/sec!
Mac or PC.

Ideal for Lightroom, Photoshop, video.
Capacity up to 16TB!
OWC Thunderblade Thunderbolt 3 SSD

Blazing fast, up to 16TB.


√ No more slow and noisy hard drives!

Save the tax, we pay you back, instantly!
View all handpicked deals...

Canon EOS 5DS DSLR Camera (Body Only)
$3699 $1299
SAVE $2400 | Terms of Use | PRIVACY POLICY
Contact | About Lloyd Chambers | Consulting | Photo Tours
Mailing Lists | RSS Feeds | Twitter
Copyright © 2020 diglloyd Inc, all rights reserved.
Display info: __RETINA_INFO_STATUS__