Precision 690 - initially too slow, but sloved

Hi, I just tried Sandra 2007 on my Precision 690 and got much higher memory bandwdith numbers than you see. 

Benchmark Results
RAM Bandwidth Int Buff'd iSSE2 : 6664 MB/s
RAM Bandwidth Float Buff'd iSSE2 : 6665 MB/s
Results Interpretation : Higher index values are better.

Int Buff'd iSSE2 (Integer STREAM) Results Breakdown
Assignment : 6751MB/s
Scaling : 6869MB/s
Addition : 6605MB/s
Triad : 6432MB/s
Data Item Size : 16 byte(s)
Buffering Used : Yes
Offset Displacement Used : Yes
Bandwidth Efficiency : 63% (estimated)

Float Buff'd iSSE2 (Float STREAM) Results Breakdown
Assignment : 6667MB/s
Scaling : 6875MB/s
Addition : 6573MB/s
Triad : 6548MB/s
Data Item Size : 16 byte(s)
Buffering Used : Yes
Offset Displacement Used : Yes
Bandwidth Efficiency : 63% (estimated)

Sorry, I just see I posted the wrong memory bandwith number. It should have been

RAM Bandwidth Int Buff'd iSSE2 : 2583 MB/s
RAM Bandwidth Float Buff'd iSSE2 : 2853 MB/s

of course...

Still, you've got more than twice as much. How can this be?
What CPU and memory configuration do you have?

We have a single XEON 5050 (dual core, 3.0 GHz) with 2 GB RAM, which, according to the BIOS, runs in Dual channel mode. FSB at 667 MHz and memory at 533 MHz. Pretty strange, I think...

Thanks for reply!

So, your configuration is quite a bit different than mine.  That probably explains the difference in our numbers.

I've got two Xeon 5130 CPUs (2.0GHz with 1333 FSB) and four 1GB 667MHz DIMMs.

When you install four matched DIMMs, you get quad channel memory mode with is faster than dual channel.  Also, my FSB and memory clock speeds are faster than yours.

 

Message Edited by ntheno on 07-31-200610:02 AM

---

@ntheno wrote:

So, your configuration is quite a bit different than mine.  That probably explains the difference in our numbers.

I've got two Xeon 5130 CPUs (2.0GHz with 1333 FSB) and four 1GB 667MHz DIMMs.

When you install four matched DIMMs, you get quad channel memory mode with is faster than dual channel.  Also, my FSB and memory clock speeds are faster than yours.

 

Message Edited by ntheno on 07-31-200610:02 AM

---

Indeed.  Excellent point.

Great - I KNEW it was a drive issue.  Write speeds are horrendous.

So we're using the SAS controller for a mirrored raid configuration.  Sounds  like this isn't going to work if we really want to USE the system.

Hi,
Got same problem with memory speed...
I have 2 x 2 Gb, and sisandra gave a bandwith half of the one I got on a 670
RAM Bandwidth Int Buff'd iSSE2 1707 MB/s
RAM Bandwidth Float Buff'd iSSE2 1700 MB/s
I haven't found settngs in BIOS or what to do to solve that issue.
I'm running XP64, and we got that problem on several machine in my company.

I sent that to Dell support, and waiting for answer...

Yannick

Interesting test.
Well, the Sales rep didn't suggested it to me, so I supposed it was fine with 2 Dimms only.
So if those machine are not able to run properly with only 2 DIMMS, they should not sell them this way. It is not the customer to have to guess what is the proper config to run it.

Also they are running anyway in Dual channel, so I didn't expect it to be too soo slow.
And note that I have a power edge with also only 2 Dimms, and I got a bandwith around 5000 MB/s.
Even on 3 years old PC, medium range, I have a bandwith around 4000 MB/s.

I will see if I can get some memory from DEll, and do a test. I will keep youposted with Dell support answer.

Thanks

Hi Yannick,

If memory performance and bandwidth was important to you, why did you just get 2 DIMMs?  See the note on the Dell order page:

The Dell Precision 690 has a quad memory bus architecture, Dell recommends that all four memory channels be populated with DIMMs for maximum performance.

On my system, I have four 1GB 667MHz DIMMs and got a Sandra score of ~6600 MB/s.  As a test, I just removed two and ran the benchmark with two 1GB 667MHz DIMMs and got a score of ~2500 MB/s.

Here is a good and quick article on FB DDR2
http://www.anandtech.com/mac/showdoc.aspx?i=2811&p=4

Was painful, long and difficult, but got Dell to exchange my 2 Dimms, by 4 Dimms.
That get my analysis performance to reasonable value.

But for a 3.8 GHz, this machine is similar as a precision 670 with a 3.4 GHz processor.

So I'm not really enthousiast about those 690, and by the fact that Dell is selling those machine without 4 Dimms by default...

I have a Precision 690, specs:
1 Xeon 5150 @ 2.66 Ghz
4 GB RAM (4 1GB DIMMS)
2 500 GB Hitachi drives

I have the drives set up in a RAID mirror on the SAS controller and I have this same problem with horrible drive performance.

If I'm installing a few GB of data or copying anything to the RAID drives the system performance absolutely dies. I can't even browse the web at times it's so slow.

After doing some tests, eliminating the anti-virus program I'm using, etc. I found this thread and decided to boot from one mirror drive as SATA and BAM! Problem gone.

A few stats for copying an approximately 1GB file around using explorer in XP SP2:

SAS:
Copy from USB 2.0 7200 to SAS RAID: ~ 2 minutes 44 seconds
Copy from one SAS RAID partition to another: ~ 3 minutes 20 seconds
Copy from SAS RAID partition to USB 2.0 7200: ~ 42 seconds

SATA:
Copy from USB 2.0 7200 to SATA partition: ~27 seconds.
Copy from one SATA parition to another: ~ 1 minute 16 seconds
Copy from SATA partition to USB 2.0 7200: ~ 44 seconds

As you can see, copying from the USB to the Dell internal drives got 6X faster with SATA. Copying between internal partitions (on the same physical drive) got about 2X faster with SATA. The read times for the SATA appear to have remained about the same.

I'm not sure if this is not out of the oridinary for RAID mirrors, but my own experience tells me it is. No way I'm using the SAS RAID now. Too bad I didn't know this before setting up this machine and recopying all of my data.

Also I have a friend with the exact same system and RAID setup (both purchased by our employer for home use) and his times were nearly identical.