754 or 939 if two different brands of pc3500 memory ?

[junkstockbox]

I am wanting to take the athlon 64 plunge and have about a 2 year old original stick of 512mb OCZ pc3500 (probably cas2.5) and a stick of PNY Verto PC3500 which is definately cas 2.5 both running fine at 184fsb on my athlon xp 2800+. I want to use both these in a new athlon 64 setup. Since they are both PC3500 which is more than the required pc3200, even though different brands, can I use them in the dual memory channel socket 939 new athlon mobos like the Asus a8v, or should I stick to the old socket 754 motherboards and single channel? I don't want to have to buy new matched pair memory modules and I hear a lot of motherboards are finakey about the memory. Are the socket 754 or 939 the fineky ones? Any comment on if my memory would work with the Asus A8V would be appreciated.
Thanx

[infinitevalence]

You may beable to use them but its very unlikly that you will. There may be more differnces than you know between the sticks. The reason why you need matched pairs or at least the same type of memory from the same manufacturer is because dual chanal takes two sticks and rather than map each one seperatly it maps it as one larg chunk of memory.

[junkstockbox]

Well, here is some info I got from cpuid:
CPU-Z version 1.21
Memory Modules Serial Presence Detect (SPD)
Module #1
Manufacturer (ID) (FFFFFFFFFFFFFFFF)
Size 512 MBytes
Max bandwidth PC3200 (200 MHz)
Timings table
Frequency (MHz) 200
CAS# 2.5
RAS# to CAS# delay 4
RAS# Precharge 4
TRAS# 9

Module #2
Manufacturer (ID) (7FBA000000000000)
Size 512 MBytes
Max bandwidth PC3200 (200 MHz)
Timings table
Frequency (MHz) 200
CAS# 2.5
RAS# to CAS# delay 3
CAS# Precharge 3
TRAS# 8

Both these sticks are PC3500, yet it reports pc3200 (maybee because pc3500 isn't a standard) anyways, these 2 sticks work perfectly together at cas 2.5 by spd at 200mhz fsb on my athlon xp.
SO, are you saying I should stick with the single channel athlon 64 socket 754 to be able to use both sticks or should I go with the newer socket 939 mobo because I will probably only be able to use one stick anyways? These 2 sticks seem awefully close in specs, do you really think they won't work together on socket 754 or 939?
Thanx

[infinitevalence]

Im saying that if you want to use s939 then you will want matched pairs or at least the same kind from the same manufactuer. If you decide to go s754 then you can keep the ram you have. But there are enough differences between the sticks that i cannot tell you if they will or will not work together in dual channal but i dont think they will.

[Apoptosis]

Basically you have a chance that those modules will work at relaxed timings... IE: 2.5-4-4-9 More than likely the IC's (lil black chips) on the two modules are different. This play a more important roll than the main timings as you can set those in the BIOS.

[junkstockbox]

I'm now thinking maybe I should get the MSI k8neo platinum 250gb motherboard. It has proven agp/pci locks and overclocks like a champ with an athlon 64 3200+ I could use my memory and spend about $400 rather than getting a socket 939 mobo and 3500+ for $600. I would spend the extra $200 IF I was pretty sure I could get the memory sticks working, don't want to buy memory. But if socket 754 board will definately work with these two sticks, I would get that, save $200, and when PCI express/DDRII comes out go for another upgrade later.. So will these 2 sticks work in the single channel socket 754 boards for sure just like in my 200fsb athlon 3200+ cas 2.5, 4,4,9?

[Apoptosis]

That sounds like the safe choice all around. If I was a betting man I would think you could get your modules to run CL2.5 just fine on that board also. IF you get it you'll have to let us know how it all goes.

[junkstockbox]

I was reading the asus a8v socket 939 specs and it says it can work with 266/333/400 ram. So I assume I could set my old pc3500 ram sticks to the 333 setting, then overclock the fsb a bit and overclock the processor to boot! And find a happy memory setting somewhere between 333 and 400, or if the two sticks are not exactly the same they won't work dual channel even if highly relaxed????

[junkstockbox]

Filling you in on my decision. I went with the Asus A8V and 3500+
My 2 different sticks of pc3500 memory worked fine together at
dual channel 200fsb at autodected relaxed settings, but wouldn't even go
past 210mhz.
SO...I lowered the memory divider to 333 (5/3) and raised the fsb to 228
there is NO AGP/PCI lock and I am running completely stable at 2500mhz!
Thats like an athlon64 3900+ with all tight 2,2,2,5 memory settings at in
essence 180mhz x 2 =360mhz and my sandra memory is 5400 same as
an opteron. Sure I could buy a $350 dual channel ddr kit and get 5900 sandra marks, but it makes no real world difference and my system went
from 2200 mhz to 2500 mhz at 1.6v on thermalright slk-948u and 38cfm fan.
The system rocks. But I have heard a rumor that athlon 64 dual channel likes a slow setting of about 10 on one part of the memory and it is actually faster, can someone fill me in on the name of that bios setting to be switched up to 10.
Thanks

[infinitevalence]

change it to 2-2-2-11.

[Apoptosis]

The standard memory specs for latencies are expressed in this format: CAS-tRCD-tRP-tRAS, or in the BIOS for example: 2-3-3-7.

In your case you want to change the tRAS [Row Address Strobe (RAS) Pulse Width] higher...

11 seems to be the going setting for your system.

hope this helps!