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...
Amazon
As an Amazon Associate I earn from qualifying purchases.
Up to 1527MB/s sustained performance
877-865-7002
Today’s Deal Zone Items... Handpicked deals...
$180 $100
SAVE $80

$699 $479
SAVE $220

$4900 $3000
SAVE $1900

$2299 $1799
SAVE $500

$1798 $1598
SAVE $200

$3508 $2998
SAVE $510

$1099 $999
SAVE $100

$1099 $999
SAVE $100

$2797 $2497
SAVE $300

$1499 $1349
SAVE $150

$1499 $1299
SAVE $200

$2598 $2398
SAVE $200

$3998 $2998
SAVE $1000

$3498 $2998
SAVE $500

$1199 $1099
SAVE $100

$240 $175
SAVE $65

$1499 $1349
SAVE $150

$2799 $2499
SAVE $300

$7999 $6999
SAVE $1000

$250 $210
SAVE $40

$1199 $1099
SAVE $100

$799 $599
SAVE $200

$999 $949
SAVE $50

$1999 $1449
SAVE $550

$2799 $2499
SAVE $300

$449 $389
SAVE $60

$400 $300
SAVE $100

$1699 $999
SAVE $700

OWC Thunderblade Thunderbolt 3 SSD

Blazing fast, up to 16TB.

YEE HAH!



√ No more slow and noisy hard drives!

How to test memory for reliability

2009-06-01 - Send Feedback
Related: how-to, memory

When you install new memory (or you suspect existing memory), the first thing to do is to verify that it’s present in About This Mac. Clicking the More Info button brings up the System Profiler window; click on Memory to see memory status.

If this is a Mac Pro, the memory will be ECC (error correcting code) memory, and “Status” will show errors if present. There should almost never be ECC errors, though (quite literally) cosmic rays occasionally can induce them, especially at high altitude. Machines without ECC memory just tend to crash when there are errors; errors go undetected and uncorrected.

Memory tends to fail under stress, and stress means heat. The best way to detect latent memory problems is to make the machine hot, to raise its operating temperature. Sub-standard memory will often fail under such conditions, ECC memory will show ECC errors, etc.

For a robust system test, run the MemoryTester stress test for at least one hour. An overnight test (8 hours or longer) is even better—you can’t possibly use the machine that hard in normal use! If the test completes without a crash (the usual result of flaky system), then you’ve got a clean bill of health. On the Mac Pro, there should be no ECC memory errors after any test, so if there are, get the memory exchanged immediately.

A typical MemoryTester stress test run looks like what’s shown below. Activity Monitor will show all CPU cores fully utilized.

llcMP:~ lloyd$ nice dlt run-stress-test --memory-per-thread 4G --duration 8h
MemoryTester 1.1.0 64-bit
Copyright 2006-2008 diglloyd, Inc. All Rights Reserved.
Tuesday, November 25, 2008 10:36:58 AM PT
Physical memory (MB): 32768
********************************** Stress Test *********************************
System memory: 32GB
Test duration: 8h
CPU percent: 100% (per cpu core)
Num CPU threads: 4
Memory per thread (requested): 4GB
==> Determining amount of non-pageable memory
(this phase can take several minutes before stress-testing begins)
Checking for virtual memory paging for 16GB
No paging detected for 4GB (good)
No paging detected for 8GB (good)
No paging detected for 12GB (good)
No paging detected for 16GB (good)
Allocated 4GB per thread (16GB) for 4 threads, reverifying paging behavior...
Done determining pageable memory.
NOTE: Avoid starting applications while tests are running;
system response will be very sluggish.
Memory usage per thread: 4GB
Volumes to test: none
Creating 4 CPU thread(s) at 100% utilization,
each consuming 4096MB for a total memory use of 16GB
1 2 3 4  
Starting...
1 2 3 4  started.
Waiting for all threads to start...
All threads were started.
Thread 0 started OK.
Thread 1 started OK.
Thread 2 started OK.
Thread 3 started OK.
4 cpu threads started successfully using a total of
16GB of memory, to be accessed continually.
=====> Use ctrl-C to stop ^lt;=====
Note: speeds denote memory copying speed (memmove);
multiply by 2 for total bandwidth.
10s: 16384MB @ 2846 MB/sec (best)
20s: 16384MB @ 2909 MB/sec (best)
...

 

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 Pro Elektron

Ultra-high performance across entire capacity, outperforms the competition.

Tiny, bus-powered, rugged, compact!


√ 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!

Deals Updated Daily at B&H Photo
View all handpicked deals...

Venus Optics Laowa 105mm f/2 Smooth Trans Focus Lens for Sony E
$699 $479
SAVE $220

diglloyd.com | 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__