Dual Channel mode has no speedup on my 7NNXP

[Bob]

Archived from groups: alt.comp.periphs.mainboard.gigabyte (More info?)

Hi,

I have a new system and I tried running the SiSoft Memory Benchmark
with a single 512MB DIMM in slot 1, and compared it against one in slot 1 and one
in slot 4 (I tried slot 3, but my system kept getting errors during bootup,
either "Memory Protection Errors" or errors in VxD, this is with WIN98SE
and limiting the available memory to 512MB with Cache Manager (because it
turns out WIN98 is unstable with memory >512MB according to many sources)).

I get identical results on the memory benchmarks. When I use two DIMMs
the BIOS does report that it's running in Dual Channel mode, however.
I'm using PC3200 memory, and an Athlon XP 2800+ 333Mhz FSB processor.
The System Jumper (CLK_SW) is set to ON/Auto.

Why would I not be seeing any memory speedup with Dual Channel mode?
My BIOS settings are FSB 166 MHz and and memory freq SPD. The results
of the benchmark say the speed is comparable to PC2100/DDR266 memory.

BTW, the manual is not clear on the memory freq settings. What is "SPD"
and "Auto"?

Any insight would be appreciated. It was really odd that I couldn't use
slots 1 and 3. Anybody else have this problem? Both my DIMMS are DS.

-Bob

 

[Guest]

Archived from groups: alt.comp.periphs.mainboard.gigabyte (More info?)

Dealing with things in the order in which you list them.

To get Dual Channel working you you either need to use the combination of
slot 1 & 3, 2 & 4, or if you have 4 single sided modules 1 2 3 & 4, using
slots 1 & 4 or 2 & 3 will not enable Dual Channel on the 7NNXP.

Dual Channel mode is extreemly fussy about its RAM though this has been
alieviated since (if my memory serves correctly) about the F15 BIOS, I would
suggest you upgrade the BIOS to F18 or later and try again. You may still
have problems with Dual Channel even with this BIOS, it depends on the
manufacturer of the RAM, and trying to use two different makes/varients of
modules is almost bound to failure.

WIN98 is not unstable with more than 512Mb of ram, just a bit pointless due
in part to the way windows cache works.

Regards Benchmarking, what were you expecting to see? Using Dual Channel,
the memory pathways to the CPU are still the same as they allways have been,
its only the bandwidth of the memory pathway to the support chips which
increases. For example this means if your video card is keeping textures in
main memory they can be retrieved much faster, and the same goes for your
sound card, HDDs, infact anything that makes Direct Memory Access transfers!

Best of luck

Crimson Liar



"Bob" <bobdbitbucket@netscape.net> wrote in message
news:e6696cf0.0406191947.48c2df28@posting.google.com...
> Hi,
>
> I have a new system and I tried running the SiSoft Memory Benchmark
> with a single 512MB DIMM in slot 1, and compared it against one in slot 1
and one
> in slot 4 (I tried slot 3, but my system kept getting errors during
bootup,
> either "Memory Protection Errors" or errors in VxD, this is with WIN98SE
> and limiting the available memory to 512MB with Cache Manager (because it
> turns out WIN98 is unstable with memory >512MB according to many
sources)).
>
> I get identical results on the memory benchmarks. When I use two DIMMs
> the BIOS does report that it's running in Dual Channel mode, however.
> I'm using PC3200 memory, and an Athlon XP 2800+ 333Mhz FSB processor.
> The System Jumper (CLK_SW) is set to ON/Auto.
>
> Why would I not be seeing any memory speedup with Dual Channel mode?
> My BIOS settings are FSB 166 MHz and and memory freq SPD. The results
> of the benchmark say the speed is comparable to PC2100/DDR266 memory.
>
> BTW, the manual is not clear on the memory freq settings. What is "SPD"
> and "Auto"?
>
> Any insight would be appreciated. It was really odd that I couldn't use
> slots 1 and 3. Anybody else have this problem? Both my DIMMS are DS.
>
> -Bob

 

[Bob]

Archived from groups: alt.comp.periphs.mainboard.gigabyte (More info?)

Are you saying the mobo manual is wrong? Because it clearly
says that I can use dual-sided DIMMS in slots 1 and 4 and get
Dual Channel Mode, and in fact that's what the BIOS announces
during bootup.

Thanks for the note regarding expected memory performance.
I thought the interleaving would result in better memory
bandwidth to the CPU as well, but apparently not.

Thanks,
Bob

"CrimsonLiar" <trash@trash.com> wrote in message news:<4%dBc.730$x25.359@newsfe4-gui>...
> Dealing with things in the order in which you list them.
>
> To get Dual Channel working you you either need to use the combination of
> slot 1 & 3, 2 & 4, or if you have 4 single sided modules 1 2 3 & 4, using
> slots 1 & 4 or 2 & 3 will not enable Dual Channel on the 7NNXP.
>
> Dual Channel mode is extreemly fussy about its RAM though this has been
> alieviated since (if my memory serves correctly) about the F15 BIOS, I would
> suggest you upgrade the BIOS to F18 or later and try again. You may still
> have problems with Dual Channel even with this BIOS, it depends on the
> manufacturer of the RAM, and trying to use two different makes/varients of
> modules is almost bound to failure.
>
> WIN98 is not unstable with more than 512Mb of ram, just a bit pointless due
> in part to the way windows cache works.
>
> Regards Benchmarking, what were you expecting to see? Using Dual Channel,
> the memory pathways to the CPU are still the same as they allways have been,
> its only the bandwidth of the memory pathway to the support chips which
> increases. For example this means if your video card is keeping textures in
> main memory they can be retrieved much faster, and the same goes for your
> sound card, HDDs, infact anything that makes Direct Memory Access transfers!
>
> Best of luck
>
> Crimson Liar
>
>
>
> "Bob" <bobdbitbucket@netscape.net> wrote in message
> news:e6696cf0.0406191947.48c2df28@posting.google.com...
> > Hi,
> >
> > I have a new system and I tried running the SiSoft Memory Benchmark
> > with a single 512MB DIMM in slot 1, and compared it against one in slot 1
> and one
> > in slot 4 (I tried slot 3, but my system kept getting errors during
> bootup,
> > either "Memory Protection Errors" or errors in VxD, this is with WIN98SE
> > and limiting the available memory to 512MB with Cache Manager (because it
> > turns out WIN98 is unstable with memory >512MB according to many
> sources)).
> >
> > I get identical results on the memory benchmarks. When I use two DIMMs
> > the BIOS does report that it's running in Dual Channel mode, however.
> > I'm using PC3200 memory, and an Athlon XP 2800+ 333Mhz FSB processor.
> > The System Jumper (CLK_SW) is set to ON/Auto.
> >
> > Why would I not be seeing any memory speedup with Dual Channel mode?
> > My BIOS settings are FSB 166 MHz and and memory freq SPD. The results
> > of the benchmark say the speed is comparable to PC2100/DDR266 memory.
> >
> > BTW, the manual is not clear on the memory freq settings. What is "SPD"
> > and "Auto"?
> >
> > Any insight would be appreciated. It was really odd that I couldn't use
> > slots 1 and 3. Anybody else have this problem? Both my DIMMS are DS.
> >
> > -Bob

 

[Guest]

Archived from groups: alt.comp.periphs.mainboard.gigabyte (More info?)

>
> Regards Benchmarking, what were you expecting to see? Using Dual Channel,
> the memory pathways to the CPU are still the same as they allways have been,
> its only the bandwidth of the memory pathway to the support chips which
> increases. For example this means if your video card is keeping textures in
> main memory they can be retrieved much faster, and the same goes for your
> sound card, HDDs, infact anything that makes Direct Memory Access transfers!
>
> Best of luck
>
> Crimson Liar

Very Very true and correct. Dual channel DDR in Athlon XP processors
doesnt have much of perfomance gain over single channel ddr simply
because the pathway between the processor and the motherboard
chip(northbridge chip) remains 64 bit at 333/400 Mhz. So maximum
bandwidth between Athlon and northbridge is 400*64/8=3.2GB/s while
maximum bandwidth between northbridge chip and dual channel memory is
6.4GB/s. The extra bandwidth goes as you said to agp transfers,PCI
cards and harddisks/DVD/CD roms and generally anything that uses
Direct Memory Access. During a game harddisks and DVD/CD work only
during the beginning of each level, where data are loaded, therefore
you cant expect to have a significant perfomance gain.
In Intel processors where the bus remains 64 bit but frequency goes up
to 800mhz, dual ddr400 fully meets the need of CPU at least
theoretically. Yet from testings i have done to a friends PC with an
Intel 3.06Ghz and Dual channel DDR the perfomance gain is more or less
the same as to Athlon case. Maybe the bottleneck in all games is the
GPU speed . Only with the latest X800XT and geforce 6800 the
bottleneck may shift to CPU/Memory bandwidth.

 

[Guest]

Archived from groups: alt.comp.periphs.mainboard.gigabyte (More info?)

I was going to quote the manual to you, but it appears im wrong on the
channel business. Channel A being DIMM slots 1 & 2, and Channel B being DIMM
slots 3 & 4, so according to the manual as long as the amount of ram on each
channel is the same it should work (tho as its fussy about ram types speeds
etc...).

Regards expected memory performance to the CPU, there is a small gain but is
probably no more than a 2%-5%.

Crimson Liar

"Bob" <bobdbitbucket@netscape.net> wrote in message
news:e6696cf0.0406201902.405815fa@posting.google.com...
> Are you saying the mobo manual is wrong? Because it clearly
> says that I can use dual-sided DIMMS in slots 1 and 4 and get
> Dual Channel Mode, and in fact that's what the BIOS announces
> during bootup.
>
> Thanks for the note regarding expected memory performance.
> I thought the interleaving would result in better memory
> bandwidth to the CPU as well, but apparently not.
>
> Thanks,
> Bob
>
> "CrimsonLiar" <trash@trash.com> wrote in message
news:<4%dBc.730$x25.359@newsfe4-gui>...