4 Sticks of RAM

[mubs]

I have 2 x 1 GB of dual-channel RAM on my NForce 4 motherboard (DFI Lanparty UT SLI DR Expert - I hope I got that mouthful right). CPU is a Socket 939 X2 4400.

1) If I add 2 more sticks of dual-channel RAM, will memory speed slow down (because all slots are full)? I vaguely remember reading 2T instead of 1T with all slots full. I think this applies to older systems, though.

2) Ignoring any effect from #1, if I add another 2 sticks, will there be a slowdown with an extra 2 GB as compared to an extra 1 GB?

Thanks, as always!

 

[ddrueding]

My vague remembrance is is that your vague recollection is correct. Once you stray from 2 sticks it slowed down. But, if you are actually needing 2GB+, it will certainly be faster to have it!

 

[MaxBurn]

Pretty sure you are right. My old game computer with 3700+ San Diego would not do 4 sticks at the correct speed and 1T with Corsair Value ram. I think that was a Gigabyte nforce board at the time too? You could either lower the speed down on the memory and keep the same timings or go to 2T at full speed.

I moved all that memory to my server which is a P43.0c on a Supermicro P4SCT and it runs fine at tight timings 1T and full speed with no issue in the last eight months or so.

For the game computer 3700+ I had to go with two 1gig sticks to run tight timings at full speed.

 

[mubs]

Well, it looks like 4 sticks will slow things down.

Anbody know about #2?

 

[Mercutio]

I think that you'll find the real-life difference between memory timings is one of those things that more or less only makes a difference in synthetic benchmarks; the real-world advantage of a 4GB configuration for someone who needs a 4GB configuration (ie, already using more than 2GB RAM) more than outweighs whatever slight losses might occur as a result of the upgrade.

 

[sechs]

I'll second what Merc said.

I run ECC memory on my Opteron system and can't tell the difference between it being on or off. I jave one set of sticks with the pedestrian server/workstation timings and another set with the much tighter enthusiast timings; I cannot tell the difference.

 

[MaxBurn]

Well yes, all else being unequal due to timing, if you need that much memory it will be much better than not having it, so I agree +4 on what ddrueding said.

 

[Sol]

I'm fairly cirtain that DFI Lanparty boards slow the RAM by default for 4 sticks but allow you to over-ride that setting if your confident that it will work (or just want to see).

But also what everyone else said, if you'll use the RAM then it'll be faster to have it anyway.

 

[Clocker]

My experience is that the ram latentcy is change to 2T but also the frequency is cut in half, at least with the A64 CPUs.

http://www.storageforum.net/forum/showthread.php?t=6263&highlight=Vista+Ultimate+x64+4GB+RAM

 

[sechs]

Doesn't that have to do with the chip revision?

I know that the CG revision chips that I originally had would dump the memory frequency down a grade if I installed four sticks on a single processor, but the E0 chips that I have now don't do that.

 

[Clocker]

I had a relatively new Toledo Core X2 processor so I'm not sure how to tell which ones would do it and which ones would not. I think the AM2 processors are less prone to this issue rather than the S939 one I had.

 

[mubs]

Crap. DDR RAM is so expensive compared to DDR2. I'd hate to buy it and have to pull it out. I'll have difficulty selling it if I'm not going to use the extra RAM.

I don't know what rev my CPU is. I'm away from home and will have to call the wife and walk her thru running CPU-Z. According to Wikipedia, Windsor was released on May 23, 2006, and I had already built my system then. So mine must be a Toledo, but will confirm.

 

[mubs]

I finally located the motherboard manual. They clearly state that 4 DIMMs will drop the speed from DDR400 to DDR333.

The integrated memory controller in AMD's 64-bit Socket 939 series CPU will directly catch data transmission from DDR RAM without passing through the Northbridge. Therefore when using 4 identical double side DIMMs or using 2 DIMMs in non-dual channels, the memory speed will reduce to DDR333.

They don't state it here, but elsewhere state that timing also has to be increased from 1T to 2T.

The real issue is how much a real-world performance hit there will be.

Sigh. Why does life have to be so complicated.

 

[MaxBurn]

Yes, thats what my board did by default when you populated all four slots. Manually setting the same fast timings at DDR400 caused all sorts of memory problems. Mine was a San Diego CPU.

http://www.storageforum.net/forum/showthread.php?t=5399&highlight=memory

 

[sechs]

I think that the manual for my board said the same thing. Obviously, it was in reference to the chips available at the time, and not a real limitation of the motherboard hardware.

Can't DFI tell you whether this will work? Hasn't anyone else in the whole world with this board tried four sticks?

 

[ddrueding]

I seem to recall this being an issue with all S939 chips, and not an issue with AM2. I know I'm not having any issues now, but I remember specifically limiting myself to 2GB of RAM when @ S939.

 

[mubs]

Thanks for the link, Maxburn; I had forgotten about that thread. I agree with you; I don't want to overclock, just use all the DIMM slots in my motherboard. My board is supposed to have special circuitry, power and Nichion caps to enable the memory to work well. It amazes me that we still have to compromise on speed if we want to max the memory.

My retail S939 A64 X2 4400+ was packed in the 43rd week of 2005 (last week of October). It's a Toledo, Stepping 2, Revision JH-E6 (according to CPU-Z).

I wanted to bump up RAM for some photo work (see my Photo Scanning Help thread in the Pub & Brewery). But now there seems to be no point.

Hopefully in 5 years they would have solved stupid issues like this.

Thanks everybody.