Why is it better to overclock usingf only 2 DIMM slots vs. 4?

[Bangwhiz]

I have an Opty 165 overclocked to 2.8Ghz. I am currently running 2GB of unmatched - but same spec - value memory that passed Memtest at DDR500, if that is an accurate test. I would like to know specifically why running more RAM ( 4x1GB versus 2x1GB sticks ) lowers or complicates maximum CPU overclock speeds? Thanks.

[Bobnova]

The more ram you have the more electrical work the northbridge has to do to keep it powered and running and such.
As such, if you're overclocking the hell out of the CPU (which also forces the NB to go faster), adding more load in the form of more sticks of ram can put it over the edge.
Sometimes you can offset the extra load by strapping a fan on and cranking up the voltage, other times not so much.
Other times it's the entire mobo power circuitry that can't cut it, and in that case more volts won't help much.

It's certainly worth a shot, though the amount of money you'll have to spend to get 4x1gb of ddr500 (hell even ddr400) you could buy at least an AM2 mobo and be well on your way towards a modern system. Last time i checked that stuff was expensive.

[Evilsizer]

has to do with the memory controller... on intel for instance with the core 2's. the memory controller is on the chipset, when using 4 dimms. ocing was reduced since the memory controller was being heavily stressed. if i recall right the opty your using has a IMC? i think that the early amd's with imc has ocing issues with 4 dimms. as i havent seen or actually looked much... to see if ocing with 4 dimms was still a issue for amd. i have seen newer intel LGA1156's running 4 dimms with what i would call high oc's. that in the past wouldnt have happened on core 2. though i seem to be one of the few with a core 2 system running 4x1gig sticks and ocing. though the fsb is only 400mhz, only a small vdimm bump was needed to get the rig stable.

im sure if this question was posted in the amd section. you would prolly get a better response then mine.

[Bangwhiz]

The more ram you have the more electrical work the northbridge has to do to keep it powered and running and such.
As such, if you're overclocking the hell out of the CPU (which also forces the NB to go faster), adding more load in the form of more sticks of ram can put it over the edge.
Sometimes you can offset the extra load by strapping a fan on and cranking up the voltage, other times not so much.
Other times it's the entire mobo power circuitry that can't cut it, and in that case more volts won't help much.

It's certainly worth a shot, though the amount of money you'll have to spend to get 4x1gb of ddr500 (hell even ddr400) you could buy at least an AM2 mobo and be well on your way towards a modern system. Last time i checked that stuff was expensive.

I understand where the strain would occur in my system. My Northbridge runs hot and keeping it cool has been a pain in the butt. I've used two different heatsinks on it - a passive cooled Zalman with a ghetto fan mounted over it, and a Thermatake (not sure of spelling on either of these) with a small fan, heatpipes and copper fins. Last thing I need is to put more juice or strain on that sucker. Really was a question trying to understand what impact more RAM had on overclocking and where the impact is felt. Thanks for explanations.