| Iwill DK8N
Results
Because Opterons have their memory controllers
on-die, memory performance is almost unaffected by
motherboard design and/or chipset type. Only
BIOS settings can potentially have an effect.
Memory settings such as TCAS (CAS latency), TRCD, TRAS, and TRP are
all functions of the brand and grade of memory used,
not that of the motherboard. Now if the DK8N
had VDIMM adjustments, maybe then we can
explore the value in tweaking those settings.
Thus, we are left to play with various ECC scrub
timings. Many of you out there probably are
using non-ECC memory so these scores are irrelevant.
But for those that need the extra layer of error
correction, the data below shows the effects of
various combinations of scrub settings. These
scores were obtained using Memtest86. Keep in mind that the CPUs here are
242s.
|
Memtest86 |
| L1 |
9814 MB/S |
| L2 |
3396 MB/S |
L1 and L2 transfer rates remained constant
regardless of the scrub timings.
|
Memtest86 |
|
Node Interleave: OFF, Burst length = 8 beats |
| |
DRAM BG Scrub |
L2 BG Scrub |
Data Cache BG
Scrub |
DRAM BG Scrub |
L2 BG Scrub |
Data Cache BG
Scrub |
DRAM BG Scrub |
L2 BG Scrub |
Data Cache BG
Scrub |
| |
320 mS |
40 mS |
40 mS |
640 mS |
80 mS |
80 mS |
84 mS |
40 mS |
40 mS |
| DDR |
1157 MB/S |
1179 MB/S |
1225 MB/S |
With
Node Interleave
off and DRAM Burst length at 8
beats, the DDR transfer rate is highest when the
timings are fastest. By the way, the Node Interleave
setting must be "OFF" in order for NUMA to be enabled in Windows.
|
Memtest86 |
|
Node Interleave: ON |
| |
Burst length = 8 beats |
Burst length = 4 beats |
| |
DRAM BG Scrub |
L2 BG Scrub |
Data Cache BG
Scrub |
DRAM BG Scrub |
L2 BG Scrub |
Data Cache BG
Scrub |
DRAM BG Scrub |
L2 BG Scrub |
Data Cache BG
Scrub |
| |
640 mS |
80 mS |
80 mS |
84 mS |
40 mS |
40 mS |
84 mS |
40 mS |
40 mS |
| DDR |
1488 MB/S |
1525 MB/S |
1562 MB/S |
With Node Interleave
on and DRAM Burst length at 8 beats,
the DDR transfer rate is a few hundred MB/S
higher. By switching the DRAM Burst length
to 4 beats, we reach the peak of 1562 MB/S.
Again, NUMA requires Node Interleave to be
OFF. A small bit of throughput is lost, but is
well worth the advantages of NUMA within the OS.
Windows XP SP2
installation was a breeze after fixing the MWDMA2
issue.
Also, the /pae switch was added to one line in the
boot.ini file just to be sure NUMA would be working:
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft
Windows XP Professional" /fastdetect /pae
Below are screenshots of
Sandra 2005.SR1-10.50 with various memory settings:
Node Interleave OFF:
Node Interleave ON:
Node Interleave OFF, Bank
Interleave ON:
Node Interleave OFF, ECC OFF:
As you can see above, turning off Node
Interleaving and ECC maximizes performance.
Sandra also reports the presence of the NUMA nodes.
The DK8N
has two SATA controllers - the NF3 southbridge and
the SiI3114 SATA RAID controller. Click on the
images below to view HDD transfer tests performed on
the DK8N:
|
