Memtest report, can you help reading it?

Question

Due to frequent shutdowns that have been associated with hardware issues (covered under a separate thread), I decided to run Memtest to check my RAM.
I have a total of 5 GB RAM (2 x 512MB + 2 x 2GB).  The suspicion I have is that the original, 512 is at a 4200 speed, while the added, 2 GB are rated by my Mac's System Profiler as 3200 (Crucial claimed there's no 4200 available anymore).
Also, I did a regular restart before running Memtest (via the Terminal), because when trying to start up as single-user (Command-S) I got a DOS-like screen that was not at all clear to me....  IS THAT CONNECTED WITH THE FOLLOWING MESSAGE (see below, copied from the report)? And if so, how significant is this "error" of testing with unlocked memory?
Attempting memory lock... ERROR: Memory lock failed - reason unknown.
WARNING: Testing with unlocked memory may be slower and less reliable
Here is the report, and I would greatly appreciate getting a feedback, telling me if all OK, or are there any issues with my RAM:
Last login: Fri Oct 19 17:33:46 on console
(my name)s-power-mac-g5:~ Ami$ memtest all 2
Memtest version 4.22 (64-bit)
Copyright (C) 2004 Charles Cazabon
Copyright (C) 2004-2008 Tony Scaminaci (Macintosh port)
Licensed under the GNU General Public License version 2 only
Mac OS X 10.5.8 (9L31a) running in multiuser mode
Memory Page Size: 4096
System has 2 PPC processors(s) with Altivec
Requested memory: 4531MB (4752113664 bytes)
Available memory: 4531MB (4752113664 bytes)
Allocated memory: 4531MB (4752113664 bytes) at local address 0x0000000001000000
Attempting memory lock... ERROR: Memory lock failed - reason unknown.
WARNING: Testing with unlocked memory may be slower and less reliable
Partitioning memory into 2 comparison buffers...
Buffer A: 2265MB (2376056832 bytes) starts at local address 0x0000000001000000
Buffer B: 2265MB (2376056832 bytes) starts at local address 0x000000008e9fc000
Running 2 test sequences... (CTRL-C to quit)
Test sequence 1 of 2:
Running tests on full 4531MB region...
  Stuck Address       : ok             
  Linear PRN          : ok             
Running comparison tests using 2265MB buffers...
  Random Value        : ok
  Compare XOR         : ok
  Compare SUB         : ok
  Compare MUL         : ok
  Compare DIV         : ok
  Compare OR          : ok
  Compare AND         : ok
  Sequential Increment: ok
  Solid Bits          : ok             
  Block Sequential    : ok                
  Checkerboard        : ok             
  Bit Spread          : ok               
  Bit Flip            : ok               
  Walking Ones        : ok               
  Walking Zeroes      : ok               
Test sequence 2 of 2:
Running tests on full 4531MB region...
  Stuck Address       : ok             
  Linear PRN          : ok             
Running comparison tests using 2265MB buffers...
  Random Value        : ok
  Compare XOR         : ok
  Compare SUB         : ok
  Compare MUL         : ok
  Compare DIV         : ok
  Compare OR          : ok
  Compare AND         : ok
  Sequential Increment: ok
  Solid Bits          : ok             
  Block Sequential    : ok                
  Checkerboard        : ok             
  Bit Spread          : ok               
  Bit Flip            : ok               
  Walking Ones        : ok               
  Walking Zeroes      : ok               
All tests passed!  Execution time: 15404 seconds.

Answer 1

Memtest is not an application, and it doesn't reside in the Application folder.
If it isn't an application, then what is it???
Where ever you put the Memtest Application. If it's on the Desktop, Type Desktop. If its in Downloads, Type Downloads.
but that doesn't mean my Mac is happy with the slower speed, right?
IF the RAM is, IN FACT, not PC4200 and is a slower, PC3200 DIMM, it isn't the right RAM and will cause issues, sometime, somewhere. I have a hard time believing that the machine actually runs.
hat upgrading from Tiger to Leopard made my Mac more sensitive and less stable because of it
Leopard is far more discerning regarding RAM.
Crucial claims they've sold many of thise w/o any issues. They're actually shipping me replacement RAM for free, same 3200
I don't buy it. PC5300, OK, but not slower. Many people got Crucial PC5300 and it works, but always misreports as PC3200.
What does the sticker on the side of the DIMM say?
For anyone reading (because RAM is important and misinformation and confusion is bad):
NEVER install RAM that is slower than spec'd RAM.
In the Dual Core G5, since DDR2 PC4200 DIMMs are harder to find, many people opt for DDR2 PC5300 DIMMs. That is likely fine, as the RAM will be backwards compatible to the slower 533 MHz controller of the G5.
Misreports ARE common with the faster RAM, however.
Do NOT install DDR2 PC3200 DIMMs as they are not rated beyond 400 MHz.
Power Mac G5: Memory Specifications and ... - Support - Apple