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Memory problem with Phenom II


Synchromesh

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I recently built a system with specs in the spec section. The problem that I ran into is that at 800MHz the RAM runs rock solid with no problems, however with SLI-memory enabled option system freezes periodically. I did some forum reading and manually fixed memory specs to this:

 

DRAM Configuration

Memory Voltage = 2.1v
Memory Clock Frequency = 1066Mhz
Tcl = 5
tRCD = 5
tRP = 5
tRAS = 15
1T/2T Memory Timing = 2T
Memory Hole Remapping = Enabled

CPU voltage = Auto
SLi Ready Memory = Disabled

 

Disabled legacy USB in BIOS as stated and ran memtest 2.11. Got 2 errors in RAM immediately. With 800MHz setting memtest ran without problems, with 1066 I got 2. I presume bad RAM or is there an instability chipset/CPU-related problem there somewhere? RAM is in 2x2GB configuration.

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Test both modules singly. Often with Phenom and Phenom II the issue is the memory controller and high speed memory. I advise all who ask about memory for the Phenom to stick with 800Mhz memory and those with Phenom II to stick with 1066/1333Mhz memory.

 

 

I recently built a system with specs in the spec section. The problem that I ran into is that at 800MHz the RAM runs rock solid with no problems, however with SLI-memory enabled option system freezes periodically. I did some forum reading and manually fixed memory specs to this:

 

DRAM Configuration

Memory Voltage = 2.1v
Memory Clock Frequency = 1066Mhz
Tcl = 5
tRCD = 5
tRP = 5
tRAS = 15
1T/2T Memory Timing = 2T
Memory Hole Remapping = Enabled

CPU voltage = Auto
SLi Ready Memory = Disabled

 

Disabled legacy USB in BIOS as stated and ran memtest 2.11. Got 2 errors in RAM immediately. With 800MHz setting memtest ran without problems, with 1066 I got 2. I presume bad RAM or is there an instability chipset/CPU-related problem there somewhere? RAM is in 2x2GB configuration.

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No, the same issues remain. High end DRAM still is a dice throw. Even more so now that tables for DDR3 have been added. Now > 800Mhz DDR2 are wonky and > 1333Mhz DDR3 are wonky. AMD is not creating new architectures, they are simply adding to the already issue laden hardware.

 

It is a Phenom II (940) so 1066 RAM should work fine, correct?
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So what you are saying is that there is a chance I won't be able to run this RAM at its rated 1066MHz at all?
It is dependent on the quality of the memory controller. Some do with two modules, some do not. I have never seen one that makes four modules at full speed. I advise those who are purchasing Phenom and Phenom II to go with the stock high end speed. Phenom and Phenom II with DDR2 = 800Mhz and Phenom II with DDR3 = 1300Mhz.

 

Here is how you test. Dual Channel is a function of the memory controller and not the memory. Memory is passive, it runs without errors singly at full speed or it doesn't and gives speed errors which are not physical but mean that the memory can not run at that speed. It has physical errors or it doesn't. If you test the memory at 1066Mhz in single channel and it passes clean but fails in Dual Channel, then the issue is the memory controller. All the RAM has to do is be a matched pair with identical timings and SPD settings. If the memory passes that requisite, and passes single channel but fails dual channel, then the issue is the memory controller.

 

So what you are saying is that there is a chance I won't be able to run this RAM at its rated 1066MHz at all?
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The difference between 1066 @ 5-5-5-15 and 800 @ 4-4-4-12 is very minimal with Phenom due to the ondie memory controller and thus latencies are more important than pure bandwidth.

 

Some of those processors do make the 1066 grade but many do not. There might well be methods to gain the speed but I don't know of any. This is because I have kept away from AMD since they lost the race. I had them when they won the race, ie. AMD Hammer --> XP --> 64 --> 64X2 --> Core 2 . . . and as such I haven't been in the search for those architecture.

 

I advise people to run with 800Mhz @ 4-4-4-12 if the memory can make it and usually (not always) 8500C5 can make 800C4.

 

Looks like you were correct, did 2 full passes of memtest for each stick with 5-5-5-15 @ 1066 and got no errors. Is there anything that can be done about the controller? I mean I paid extra for 1066 RAM which seems useless now.
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