Hi Richard,

Thanks for your input!

I got my Dell December 8, but if I had only waited one more week I would have been able to choose 667 MHz DIMMS :-( Dell USA had 667 MHz DIMMS for weeks before we got them here in Norway. Alas...

My servicetag: 7CPMM2J. And yes, it's 2 x 2GB @ 533MHz DIMMs.

As for the OS-es - It's all the same machine. I have tested with the preinstalled XP x64, Vista x64 (shown as Longhorn) and the current Vista 32 bit version. They all show the same dismal performance. I have yet to test XP 32, but feel that is a tragic downgrade just to get more crunching.

I'm currently running Microsoft drivers throughout, but will install the DELL Vista drivers on the current 32 bit Vista and see if it makes a difference.

Morten

Hi Morten,

Mine is a Precision 490, same as yours - service tag is F3Q1M2J if anyone wants to look (I've had a look at the support site, and I don't think that reveals anything significantly private that we haven't discussed here already!)

As you've read, it was supplied with 2 x 1GB @ 667MHz, now running at 4 x 1GB @ 667 MHz. It looks as if you have 2 x 2GB @ 533MHz, so the sizes are different as well as the speeds. But as you say, it shouldn't make that much difference.

The other major difference is the operating system. I'm running Windows XP 32-bit, as supplied by Dell OEM pre-install. On your account, I see three dual Xeons - XP Pro x64, Longhorn Pro, and Vista Pro. Are those really different machines, or are you experimenting with different OS on the same hardware? Also, x64 and Longhorn are reporting 4GB of RAM (near enough), whereas Vista is only reporting 3GB, the same as my XP32 is reporting. Could it be that you have 32-bit memory drivers running under Vista, and might that be the problem?

I'm planning to upgrade mine to Vista, too, but I've signed up for the 'Express Upgrade' program with Dell - get an OEM copy of Vista after public release, without paying an extra licence fee to M$. Dell are saying that they will ship a "Dell Upgrade DVD – includes the Dell Upgrade Assistant (tool that walks the customer through the process), BIOS, drivers, and application patches (if available).", which suggests there may still to be work to be done on the hardware support subsystems.

Let us know what you find.

Hi Richard H.,

Looking at your times I wonder if we really have the same specs! We do! I've got a DELL Precision 490 with Xeon E5320, perhaps yours is a Precision 690, but the mainboard and processor is the same. If you've got 667 MHz DIMMs it still cannot explain the etrexme differences in benchmark numbers.

My Sandra Lite (2007.2.11.17) benchmarks with 2x2 FB DIMM DDR2 SDRAM (ECC) 533 MHz:

Int: 1914 MB/s
Float: 1928 MB/s
Bandwidth efficiency: 22% (estimated)

I have rerun the benchmark several times never to get above the numbers above!

Any idea - anyone?

Regards
Morten R

Great news - Santa has visited! [well, he visited my local DHL depot, and I had to pick it up from there, but near enough.]

I re-ran SiSoft Sandra Lite 11.17b with the existing 2 x 1GB, and got

int 3,363 MB/s
float 3,386 MB/s
efficiency 40%

then installed the new DIMMs to make 4 in all

int 5,458 MB/s
float 5,477 MB/s
efficiency 64%

Fully buffered DIMMs don't seem to be readily available yet, at least not at sensible prices: in the end I went for some sold as 'generic', but stated to be MacPro compatible and pre-fitted with heatsinks - the same spec as the Dell OEM memory (DDR2 667MHz FB ECC)

The Dell BIOS doesn't allow me to change memory settings, but it does report 'Memory channel mode = Quad' in the system settings with DIMMs in slots 1 2 3 4. So I should be good to go.

BOINC seems to be counting down 'time to completion' at two seconds per second, which is also a good sign. I'll start a new chart for WUs which started after the memory upgrade, and let y'all know how it goes.

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Morten Ross

2x2gb?? you could run a complete squashed linux in ram. i bet that runs like hell

Hi Richard,

Thanks for your input!

I got my Dell December 8, but if I had only waited one more week I would have been able to choose 667 MHz DIMMS :-( Dell USA had 667 MHz DIMMS for weeks before we got them here in Norway. Alas...

Strange - mine was built in Europe (Ireland) on November 25, but I got the 667s no problem (unless they had a supply problem with the 2GB). I see that the Dell UK and USA websites are currently offering a choice of 533 or 667, but for Norway they're only offering 667 - maybe they've discovered the problem? Might be worth talking to technical support, or even claiming a manufacturing fault under warranty.

My servicetag: 7CPMM2J. And yes, it's 2 x 2GB @ 533MHz DIMMs.

You went for better hard disks, and I upgraded the graphics card, but I don't see much else that could affect speed - and neither of those should slow you down so much.

As for the OS-es - It's all the same machine. I have tested with the preinstalled XP x64, Vista x64 (shown as Longhorn) and the current Vista 32 bit version. They all show the same dismal performance. I have yet to test XP 32, but feel that is a tragic downgrade just to get more crunching.

I'm currently running Microsoft drivers throughout, but will install the DELL Vista drivers on the current 32 bit Vista and see if it makes a difference.

I think that's your best bet, unless you can get them to replace the RAM under warranty.

I think we have another Core RAC Killer...
look at this markodude[ocforums] Core(TM)2 Quad CPU@3420
CPU Time Credit
1800-1900 12.53

P.S. Mine OCed E6400 work thiese units for around 2200-2300 sec.

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I've got new (4x1 GB) 667 MHZ DIMMs, and the performance increase is more than 100%!

Int: 5325 MB/s
Float: 5333 MB/s
Bandwidth efficiency: 63% (estimated)

Was (2x2 GB 553 MHz):

Int: 1914 MB/s
Float: 1928 MB/s
Bandwidth efficiency: 22% (estimated)

I wonder what difference using all 8 DIMM sockets will make...? Anyone with all 8 slots used (with 667 MHz FB-DIMMs) are welcome to show us the Siesoft benchmarks :-)

Morten Ross

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Morten Ross

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447349745 62.21
447349820 62.21
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449136108 12.51
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Never mind the 58.7's!

How about those? I seem to have got a truckload of 60+ WUs for my 2.8 rig (overclocked to 3.045 Gig)

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I've got new (4x1 GB) 667 MHZ DIMMs, and the performance increase is more than 100%!

Int: 5325 MB/s
Float: 5333 MB/s
Bandwidth efficiency: 63% (estimated)

Was (2x2 GB 553 MHz):

Int: 1914 MB/s
Float: 1928 MB/s
Bandwidth efficiency: 22% (estimated)

I wonder what difference using all 8 DIMM sockets will make...? Anyone with all 8 slots used (with 667 MHz FB-DIMMs) are welcome to show us the Siesoft benchmarks :-)

Morten Ross

That looks more like it! Did you have to buy the RAM yourself, or did you persuade Dell to swap it?