Stay with 2GB in Dual Channel or goto 3GB in Single Channel?

[Ryland]

My evga NF41 motherboard is really not liking having all 4 memory slots filled since it says it is running the memory at DDR200 speeds instead of DDR400 speeds AND it is only seeing 3.7 gig out of the 4 gig. The speed change forced my Vista performance score to drop from 4.9 to 4.3. Would I see a large performance hit if I pulled one of the sticks (so only 3 slots are filled) which would hopefully kick my speed back up to DDR400 but be in single channel?

 

[blackangst1]

As far as memory recognition...Im assuming youre using Vista 32? If so, it wont see 4 gigs. Period. Limitation of 32 bit systems.

As far as performance scores...meh. I dont even bother with them. Worthless IMO. Dont worry about it.

 

[Ryland]

I am using Vista64 actually but my motherboard has a problem with 4gigs of memory in that it takes into account all system memory (including video card). I haven't found a setting to stop it from doing this yet.

 

[conlan]

Try adding a 2 x 512MB kit for a total of 3Gb dual-channel, then you'll know if it's a total memory problem, or a DIMM slot problem

 

[Ryland]

I am going to use CPU-Z tonight to see what the SPD's say on the various DIMM's. I don't have a 1GB kit lying around to test.

 

[Nothinman]

As far as memory recognition...Im assuming youre using Vista 32? If so, it wont see 4 gigs. Period. Limitation of 32 bit systems.

Actually it's a limitation of 32-bit Windows, other 32-bit OSes can address >4G of memory just fine.

I am using Vista64 actually but my motherboard has a problem with 4gigs of memory in that it takes into account all system memory (including video card). I haven't found a setting to stop it from doing this yet.

That doesn't make any sense. With PCIe the video memory has to be addressable and will get mapped somewhere below the 4G space but it shouldn't affect the total amount of memory that the firmware sees. Or maybe that's a strange side effect of how that board does memory remapping.

 

[Ryland]

Well I am using Vista64 so the OS would be able to see memory (including any system mapped memory) beyond 4GB but my eVGA motherboard is only showing memory up to 4GB which looks like it includes system mapped memory. From what I have found it seems to be a known issue with the board and they should be able to fix it but whether eVGA will bother supporting an older board to do what they say it should is questionable...

 

[Nothinman]

but my eVGA motherboard is only showing memory up to 4GB which looks like it includes system mapped memory.

It has to for compatibility with 32-bit drivers so everything that needs memory mappable addresses gets them from the 4G mark and down.

 

[JustaGeek]

Originally posted by: Nothinman

Actually it's a limitation of 32-bit Windows, other 32-bit OSes can address >4G of memory just fine.

Could you please elaborate...? Which 32-bit OS can use more than 4GB of RAM?

I would appreciate some links, too.

I am not questioning your statements - just AFAIK no 32-bit OS can do that.

Thanks.

 

[alcoholbob]

Ah I guess this is the thread I actually should have been posting in...

Although I haven't seen much of a consensus, it seems many people believe there is a performance loss going from 2 sticks dual channel to 4 sticks dual channel in an AMD 939 setup.

I believe someone did a test where they upped the voltage to get the timings up to 1T after doing 2 x 1GB and 2 x 512mb, and there was some (albeit small) performance loss involved, even though the latencies remained the same (all four modules were CL2.5) I'll try to find that if I can...

 

[Nothinman]

Originally posted by: JustaGeek

Originally posted by: Nothinman

Actually it's a limitation of 32-bit Windows, other 32-bit OSes can address >4G of memory just fine.

Could you please elaborate...? Which 32-bit OS can use more than 4GB of RAM?

I would appreciate some links, too.

I am not questioning your statements - just AFAIK no 32-bit OS can do that.

Thanks.

Any that properly supports PAE meaning Linux, all of the BSDs, Windows Server, etc. Pretty much all of them except for consumer releases of 32-bit Windows.

 

[Ryland]

I feel like an idiot...I found the setting last night to force my memory back to DDR400 speeds and now everything is back in place. I guess on the last bios update they changed the memory timings from "Use SPD" to "Optimized" which was actually slower than my memory. I may try to push my memory back to 1T speeds tonight but my system is back to a 4.9 for the Vista test (it had dropped to 4.3 due to DDR200 speeds).

It still only seem 3.7GB though and I still haven't found a setting for that.

 

[pallejr]

If you have a memory remapping in your bios, it would defently be worth looking into. If nothing gets remapped, mmio will just shaddow some of your ram

 

[JustaGeek]

Originally posted by: Nothinman

Any that properly supports PAE meaning Linux, all of the BSDs, Windows Server, etc. Pretty much all of them except for consumer releases of 32-bit Windows.

Thanks - you're right. With the proper PAE support, I believe the upper limit is 64GB.



And for all others with 32-bit Windows, wondering why only 3.7GB of RAM or less is visible:

http://www.dansdata.com/askdan00015.htm

http://h20331.www2.hp.com/Hpsu...M_w-Windows_08Ap07.pdf