AMD Processors
Decrease font size
Increase font size
Topic Title: Dual & Single Channel Question.
Topic Summary:
Created On: 01/31/2005 03:22 PM
Status: Read Only
Linear : Threading : Single : Branch
Search Topic Search Topic
Topic Tools Topic Tools
View similar topics View similar topics
View topic in raw text format. Print this topic.
 01/31/2005 03:22 PM
User is offline View Users Profile Print this message

Author Icon
Le_Petit_Lapin
Senior Member

Posts: 4504
Joined: 06/07/2004

Say for example I had a Socket 754 motherboard, and a Dual Channel RAM kit (doesnt matter which). As socket 754 runs in single channel only should it theoretically overclock MORE than the same RAM than if it was in a Socket 939 motherboard (and thus Dual Channel)?

Lets imagine, for the sake of this that neither the CPU or the motherboard in either socket 754 or 939 are limiting factors.

I'd imagine the RAM running in single channel would overclock more (stabily) than if it was running in Dual Channel mode.

Its a hypothetical question really. I dont expect tests or anything, its just been playing on my mind at work today.

Thanks in advance for any awnsers!
 01/31/2005 03:34 PM
User is offline View Users Profile Print this message

Author Icon
Logan[TeamX]
Senior Member

Posts: 3185
Joined: 12/07/2003

Dual-channel RAM isn't anymore overclock-friendly than a good single stick of quality RAM. It merely means the RAM modules themselves are normally matched pairs, which lowers SPD timing discrepancies, which in turn help you achieve greater system relaibility.

So, say they were both CAS 2, 2-2-6 sticks. They're no better than a single stick of CAS 2, 2-2-5 for stock speeds or OC capability (depending on manufacturer and model of course - assume same manufacturer and model line), really. If you just buy two sticks of what's purported to be the same RAM modules, you SHOULD be ok, but the possibility exists to get two marginally different modules with different speed gradings - and we all know what happens there. Massive inconsistencies in system stability both when at factory bus speeds and while overclocking.

I hope I've been informative
 01/31/2005 03:51 PM
User is offline View Users Profile Print this message

Author Icon
ZapWizard
Senior Member

Posts: 1393
Joined: 10/06/2003

Actualy your thinking is completly backwards.

Two sticks of memory on a single channel will limit the overclocking ability more so then if each stick was on it's own channel (Dual Channel)

Why?
Memory clock speeds have many things that limit their speed, but bus capacitance or impedance is the greatest factor.

What?
Impedance, is the amount of electrical resistance to a change in voltage at a given frequency.

Huh?
What that means the higher the impedance, the slower the clock rise and fall times.
(The time it takes a signal to change from a 0 to a 1 or vis-versa)

Wha?
This means the more memory you have on a single bus, the more capacitace, the more impedance, limiting the actual maximum clock speed you can reach.

Sooo?
This is why opteron's run at 333Mhz DDR when you want to run more then four dimms or memory.
It is why 939 sockets have a maximum of 4 dimms, 2 per channel.
It is also why socket 754's have a maximum of 3 dimms, as there is only one channel.

-------------------------
' ">http://www.ZapWizard.com
The opinions expressed above do not represent the views of Advanced Micro Devices or any of their affiliates.
 01/31/2005 03:53 PM
User is offline View Users Profile Print this message

Author Icon
Le_Petit_Lapin
Senior Member

Posts: 4504
Joined: 06/07/2004

I think I worded it wrong.....I meant if you used the exact same RAM (two modules) in both the socket 754 and the socket 939 motherboard.

Would the fact that the modules when placed in the socket 754 motherboard and therefore in single channel mode, make any difference to the overclockability.

Its a silly question really as I dont see anyone downgrading from Soc. 939 to Soc. 754 for clock speeds, but anyway.


 01/31/2005 03:54 PM
User is offline View Users Profile Print this message

Author Icon
Logan[TeamX]
Senior Member

Posts: 3185
Joined: 12/07/2003

I take it that wasn't directed at me?
 01/31/2005 04:05 PM
User is offline View Users Profile Print this message

Author Icon
Le_Petit_Lapin
Senior Member

Posts: 4504
Joined: 06/07/2004

QUOTE (ZapWizard @ Jan 31 2005, 12:51 PM) Actualy your thinking is completly backwards.

Two sticks of memory on a single channel will limit the overclocking ability more so then if each stick was on it's own channel (Dual Channel)

Why?
Memory clock speeds have many things that limit their speed, but bus capacitance or impedance is the greatest factor.

What?
Impedance, is the amount of electrical resistance to a change in voltage at a given frequency.

Huh?
What that means the higher the impedance, the slower the clock rise and call times.
(The time it takes a signal to change from a 0 to a 1 or vis-versa)

Wha?
This means the more memory you have on a single bus, the more capacitace, the more impedance, limiting the actual maximum clock speed you can reach.

Sooo?
This is why opteron's run at 333Mhz DDR when you want to run more then four dimms or memory.
It is why 939 sockets have a maximum of 4 dimms, 2 per channel.
It is also why socket 754's have a maximum of 3 dimms, as there is only one channel.
Lol.....well thats me told.

Thanks!
Statistics
112018 users are registered to the AMD Processors forum.
There are currently 0 users logged in.

FuseTalk Hosting Executive Plan v3.2 - © 1999-2014 FuseTalk Inc. All rights reserved.



Contact AMD Terms and Conditions ©2007 Advanced Micro Devices, Inc. Privacy Trademark information