Athlon 64 RAM limitations?

[imported_manchild]

I read something about this somewhere but I couldn't find any info by searching the forum so I'll just ask:

Is there some sort of memory limitation with AMD Athlon 64 processors like if the RAM is PC3200 speed the processor can only have 2GB max but if it's a slower speed it can have 3GB max of RAM?

Can anyone clarify and explain that to me? Thanks.

 

[imported_whatever]

with a lot of the motherboards out there, it will not run at as tight of timings if there are more ram modules in. ie you can run tighter timings with 1 than with 2 than with 3. i havnt heard anything about the actual clock speed, though.

 

[slurmsmackenzie]

read the recent 754 roundup. it'll give you an idea. seems the dfi runs at low latencies with all three slots filled. i think that was 2 gb, though.

 

[fsstrike]

What happens if I add an extra 1Gb or 512mb Stick to my computer?
2 slots are already filled and I have 1 more free slot.

 

[Algere]

Limitation is real

e.g. if you add more than 2 double sided PC3200 memory sticks into a ASUS K8V Deluxe (K8T800) it'll downclock the ram to PC2700 operation. Although I don't know if it's a limitation of the CPU or the northbridge chipsets.

 

[LocutusX]

since the memory controller is on the CPU, it's primarily limited by the cpu. that's why the newer stepping (CG) is better on memory compatibility and performance than the old stepping (C0). however, the motherboard manufacturer still has a role to play as they can attempt to optimize trace lengths, physical placement etc. in an attempt to make the board operate "above spec" - i.e. allowing 3 DIMMs @ PC3200 speeds.

 

[imported_manchild]

It would be cool if that was better documented or if there were notes about that in the RAM configurator things like on Crucial.com so you knew that with your motherboard 3 sticks of PC3200 is really only PC2700

 

[Algere]

It says so in the K8V Deluxe manual and I'm sure some reviewers have covered it.

 

[acivick]

I think that's why a lot of boards come with only 2 slots available.

I miss the days when you could fill up 4 slots and not have to worry...

 

[Vette73]

Originally posted by: acivick
I think that's why a lot of boards come with only 2 slots available.

I miss the days when you could fill up 4 slots and not have to worry...

What boards can run 4 high speed slabs of UN-Reg Ram?

 

[acivick]

I was referring to the old Pentium 3 and I think original Athlon boards. And they were only high speed at the time.

 

[Vette73]

Originally posted by: acivick
I was referring to the old Pentium 3 and I think original Athlon boards. And they were only high speed at the time.

Yea but that was SDRAM not DDR. That and I don't remembver any of them that supported large amounts of ram in 4 banks.

3 Has been the main stay and even then there was still problems going higher with tight specs.

 

[WT]

I think that's why a lot of boards come with only 2 slots available.

I just got a Soltek K8AN2E-GR and was kinda bummed that it had only two RAM slots. After reading why the third slot was left out, I don't feel so bad. If an S754 board only has two slots, don't just assume its a cheap POS.

 

[Accord99]

Originally posted by: Marlin1975
What boards can run 4 high speed slabs of UN-Reg Ram?

Dual-channel DDR P4 motherboards and I would expect S939 to be able as well.

 

[Vette73]

Originally posted by: Accord99

Originally posted by: Marlin1975
What boards can run 4 high speed slabs of UN-Reg Ram?

Dual-channel DDR P4 motherboards and I would expect S939 to be able as well.

Yea but we are talking about SINGLE ch mem boards. Dual Ch with 4 slots to me is really 2 slots.