Q&A for the topic VERY IMPORTANT INFORMATION REGARDING AMD AM3 CPU's & RAM....

[absic]

Yes, if you are running a standard CPU (not a BE) then increasing the speed of the CPU will affect the RAM speed.

If the rated timings for your RAM at 1600MHz are 9,9,9,24 the slowing the RAM to 1333MHz should allow you to tighten them a bit. Once again though, there is no hard and fast rule for this and it is often a case of experimentation to find the best settings for your own hardware. If you want to experiment with timings you need to go to the DRAM Configuration section of BIOS and alter the DDR3 Timing Items from Auto to Manual. You can then change the numbers under the SPD Heading. You might find some figures on the Kingston site to help you get started on this.

[CrankyPants]

Alright thanks for your help, it seems I've got more than a few options. 

[OldFool]

Hi absic

In your excellent piece "VERY IMPORTANT INFORMATION REGARDING AMD AM3 CPU's and RAM SPEEDS", you state:

remember that officially, neither Gigabyte or AMD support overclocking of their products

This being the case, why did Gigabyte include EasyTune 6 on the Utilities DVD with my MB?
(I took one look at the program and set everything to default immediately)


++++++++++++++++++++++++++++++
CPU: AMD Phenom II X6 1090T BE, 6x 3.2GHz
MB: GA-870A-UD3, BIOS F5a
RAM: 4GB Corsair XMS3 Dominator DDR3-1600 CL7
Video: ATI Radeon HD 5750 1024MB passive
PSU: 550W BeQuiet! System Power

[Dark Mantis]

The thing is this is one of those grey areas as most companies support overclocking but only to an extent. They can't afford to say that they fully support it or everyone would be testing their boards/cpus to destruction and then wanting a replacement. Corporate suicide.

[pylon]

In the very useful original post it was stated:

On Gigabyte's AMD Boards there are two channels, each of which address one of the two memory controllers on the AM3 CPU. Channel 0 normally equals the Memory slots on the motherboard identified as DDR3_1 & DDR3_3 whilst Channel 1 normally refers to DDR3_2 & DDR3_4.

On the GA-870A-UD3 v2.2 (the only one I've looked at) the manual says:

The four DDR3 memory sockets are divided into two channels and each channel has two memory sockets as following: Channel 0: DDR3_1, DDR3_2Channel 1: DDR3_3, DDR3_4

Should I conclude from this that I should follow the manual's advice and use 3_1 and 3_3 for my two sticks of RAM? The thinking being that this would make use of both channels, which could then be set as unganged in the BIOS?

If the answer's yes, I'd suggest updating the original post to make it clear that people shouldn't assume 3_1 and 3_2 should be used.

[absic]

In the very useful original post it was stated:

On Gigabyte's AMD Boards there are two channels, each of which address one of the two memory controllers on the AM3 CPU. Channel 0 normally equals the Memory slots on the motherboard identified as DDR3_1 & DDR3_3 whilst Channel 1 normally refers to DDR3_2 & DDR3_4.

On the GA-870A-UD3 v2.2 (the only one I've looked at) the manual says:

The four DDR3 memory sockets are divided into two channels and each channel has two memory sockets as following: Channel 0: DDR3_1, DDR3_2Channel 1: DDR3_3, DDR3_4

Should I conclude from this that I should follow the manual's advice and use 3_1 and 3_3 for my two sticks of RAM? The thinking being that this would make use of both channels, which could then be set as unganged in the BIOS?

If the answer's yes, I'd suggest updating the original post to make it clear that people shouldn't assume 3_1 and 3_2 should be used.

Hi, in the original post I do state that:

(You would need to double check with your motherboard's own manual for correct Memory Slot Channel configuration)

Which I think covers it.

[Dark Mantis]

If the answer's yes, I'd suggest updating the original post to make it clear that people shouldn't assume 3_1 and 3_2 should be used.

To be honest I wouldn't expect anyone to expect to use the DDR3_1 and DDR3_2 slots together.

[Erik1]

Hey all... First post here.

Just wanted to say thank you for all your research and time put into this. I've been struggling with my setup for a few months now. Before I go any further I'll share my setup.

GA-MA785GMT-UD2H rev 1.1 MOBO
Phenom II X2  555BE  CPU
GSkill F3-12800CL9D-4GBRL (DDR3-1600)

When I first built the machine I had 2 x 2GB dimms that I put in slots 1 & 2. I noticed that the system was running at 1333 but didn't pay much attention. Recently Newegg had a sale so I purchases 4 gb more. This is when the problem started. When I added he next two sticks the system just continually rebooted. I've been on some other forums, Gskill told me to RMA the older RAM because of chip incompatibility which I did. Still didn't work. I tried bringing the clock down to 1333 and tightening the timings, that didn't work. Now I read your post and in 5 minutes learned more than the past two months elsewhere.
    So I guess I'm asking what you recommend to get the optimal system performance . MAybe I'll overclock the CPU a little but I want to make the most of this memory without endangering the IMC. Do I had to bring it down to 1066? Would it be better to get 2x 4gb sticks and run them at 1333?
I also noticed that the native voltage on this MOBO for the RAM is 1.6v and this particular ram is supposed to be 1.5. Should Intry reducing it? Please let me know what I can do. Thanks in advance for your help.

[Mitchiemasha]

Looks like I'll be reverting mine back to 1333. I've not had it running long enough to know if I have issues.

I got these settings from another forum.

Set System Voltage Control to {Manual}
Set DRAM Voltage Control to {1.65 volts}
Set CPU NB VID Control to {1.35 volts}
Set DCTs Mode to {Unganged}
Set DDR3 Timing Items to {Manual}
Set DRAM Timings to CL 9-9-9-24 (CL-TRCD-TRP-TRAS)
Set 1T/2T Command Timing to {2T}

See if these settings work @1600 Mhz DDR

I was concerned though because that level of voltage increase shows in red in the bios.

I have a phenom II 3.4 quad core, with 4x 2gb 1600 ocz ddr3 cards. Is there any more updates to what I should be doing, some more links would be very helpful.

Thank you.

[absic]

hi,

Not really sure what kind of updates links you are after but there is a lot of information about RAM settings on the forum for AMD systems.

If your RAM is rated at 1600MHz at 1.65 Volts then setting the voltage manually will cause a Red overvolt warning in BIOS because the system default is 1.5V. This warning can be ignored, just so long as you keep within the specified voltage range for your RAM.

The warning about running your RAM above 1333MHz is more for information as there were a lot of problems in the early days. But things have moved on a bit since I first wrote that item and whilst it is still true, there are many users running their RAM at 1600MHz who have not encountered any problems. This tends to be with the newer Phenoms and especially those with the latest stepping.

However, the reality is, that overclocking the CPU and pulling the RAM back to 1333MHz will actually give you a better overall speed increase rather than just running the RAM at 1600MHz and, if you have a BE CPU then overclocking it is much easier.

The information that you have quoted is good advice, if you want to run your RAM at their rated speed and is where I would start if I were to do that on my own system.

[Dark Mantis]

Erik1 your main problem after the difference in sticks due to the ages was that you just tried to add the extra 4GB and fill all the slots without altering all the settings. Because you filled all the banks with modules you put an added strain on the memory controller and that has to be taken into consideration with the voltages and settings. You cannot just leave them at "Auto" and expect them to work.

[Mitchiemasha]

Its true what they say, the more you learn the less you know... As it looks like I will be reading about over clocking now too. This machine I have has been sat in bits for weeks, nearly a month. Windows must have been reinstalled on it at least 20 times now. What started off as a simple upgrade has turned into a full on course into computers.

Thank you for the help. The information on this forum has been very useful. And, yes I've got the black edition 3.4 phenom II.

[ChrisB]

Hi, as a newbie to this forum, I was very interested to read all the knowlegeable posts on this topic.
I will be building myself a PC (for the first time) and have so far bought the following items:

AMD Phenom II X4 955 Black Edition
Giigabyte Mobo GA-880GA-UD3H Rev. 3.0
2x4GB Corsair DDR3 PC3-12800 Veangance 1600MHz

From reading the above posts, I think it would be safer to initially let the RAM run at 1333Mhz, to try to avoid potential insatbility problems.
How do I detemine the RAM speed setting and how would I change it?
I presume 1333MHz is the BIOS default setting? 
The MB manual doesn't appear to tell me this - or maybe I don't understand what it is telling me.

With thanks, in advance
Chris B

[Dark Mantis]

Hi

The BIOS will read the SPD on the memory to see what it is capable of and then give you the option of using severral different settings. One of these is an XMP setting which is basically a higher setting than the default frequencies allowed. If you select this setting it will then set the timings and voltage to suit.

[absic]

Hi there,

Sadly DM Is talking about Intel again and the XMP settings aren't present on AMD boards or memory which use BEMP instead (Black Edition Memory Profiles) for runing RAM autiomatically at higher frequencies.

By default, when you put your system together the BIOS will set the RAM to 1333MHz with default voltage and timings that should work straight away. Sometimes there can be issues but I wouldn't expect any from the Vengeance RAM which I have used in several recent builds and on my own system without problem.