2 DIMMs vs 4 DIMMs

[Syllabub]

After looking over the sticky on memory and culling a few pages of posts I am still puzzled. About what? About the benefits or drawbacks of using ever memory slot on a motherboard.

If I want 4GB of RAM is it:
- Better to have four 1GB sticks
- Better to have two 2GB sticks

If I want 8GB of RAM is it:
- Better to have four 2GB sticks
- Better to have two 4GB sticks

For the purposes of this thread assume that the chipset is P55 or AMD 800 series.

Please and thank you for the input.

[sttubs]

If you fill all four slots you most likely will not be able to overclock your system very well. Some motherboards may even downclock your memory, where you'd normally run 1600, could downclock to 1333. It's best to get the most Gb per stick. With the low prices you should go for the 8gb (2x4gb). If you go with the AMD system you will want to grab some memory with the lowest CL# you can find/afford (I believe CL7 is currently the lowest). I'm not sure why but they say the AMD systems run better with the lower CL#.
I am currently running these in my system: http://www.newegg.com/Product/Produc...=ripjaws%208gb
Hope this helps.

[Syllabub]

Thank you very much for the help.

Do you know if the same logic will hold true once Sandy Bridge is out and we have a new P67 chipset from Intel. I don't see why that would change anything but felt it was worth asking. It might be a bit unfair to pose the question at this time anyway since SB is still a bit of an unknown as far as the nuts & bolts details go.

[ShadowLeaper]

Thread necro!

Now that Sandy Bridge is out, we can answer the question. Sandy Bridge doesn't overclock the BCLK like other processors do, so filling all the memory slots won't pose any problems. RAM timings make minimal difference, so just go with the standard CL9 stuff to save money.

I have 12GB DDR3-1600 in my ASRock P67 Pro3 board (2x 4GB, 2x 2GB) and I have no problems overclocking.

[Poci]

I dunno about AM3 memory controlers but on previous AMD chips your memory speed was limited if all 4 dimms were populated. Even if you had say 1066 memory for example, you were forced to run 800 speeds.

I have that issue for example, if I were only running 2 dimms Id be able to do 1066 but If I try it with 4 dimms the system becomes unstable.

Its a memory controller issue, make sure you check to see if the AMD chips with DDR3 memory controller have that issue as well.

[klatch]

I have the ASUS P8Z68-V Pro and filled all four slots with 4GB Patriot 1600 sticks and had to change the command rate in the bios from "1" to "2" in order for Memtest86+ to pass. How much of a performance loss am I going to be taking from having said command rate now at "2"? I didn't actually experience any problems in Win7 with it at 1 but ran the test anyways and saw the errors with all 4 in, though each pair tested fine when they were the only pair installed.

[AMDScooter]

I ran 4x2GB PC1600 at 7-7-7-20-1t in both my P55 and current rig with no issues.

[klatch]

Your RAM has significantly better timings than mine - mine is 9-9-9-24

[Poci]

When filling all slots on AMDs you have to lower the RAM speed.
Like for example I have 1066 RAM, but the memory controller on my CPU can only do 800 mhz with all dimms populated

[Heckler]

In general, I find consumer class motherboards are less finicky if you do not use all memory DIMM slots.

[Poci]

I ran 4x2GB PC1600 at 7-7-7-20-1t in both my P55 and current rig with no issues.

You found 1T cmd rate rated RAM?!?!?! Where? I was searching for 1T last time I upgraded and couldnt find anything!!!