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Asus Crosshair and 2 x TWIN2X2048-6400C4 G


bink472

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I looked at my bios and it's running the memory at these timings:

 

5-5-5-18 2T 800Mhz

 

The memory states:

 

4-4-4-12 800Mhz

 

The system does recognize all 4gig, after some patching. :)

 

I'm just wondering if the timings set by the Bios are fine, am I losing anything there or should I try to set them to the timings stated by the memory sticks?

 

I've seen some posts about setting the voltage to 2.0, but I get confused there because of my Bios (it has multiple DDR2 voltage settings). I'm not sure which to set to 2.0:

 

DDR2 Voltage Control (auto, 1.85, 1.875 ~ 3.425v)

 

DDR2 Termination Voltage (auto, ddr2_vol/2, ddr2_vol/2 -50mv, ddr2_vol/2-100mv,ddr2_vol/2-150mv,ddr2_vol/2+50mv,ddr2_vol/2+100mv,ddr2_vol/2+150mv)

 

DDR2 Controller Ref Voltage (auto, ddr2_vol/2, ddr2_vol/2 -50mv, ddr2_vol/2-100mv,ddr2_vol/2-150mv,ddr2_vol/2+50mv,ddr2_vol/2+100mv,ddr2_vol/2+150mv)

 

DDR2 Channel A Ref Voltage (auto, ddr2_vol/2, ddr2_vol/2-100mv,ddr2_vol/2_50mv,ddr2_vol/2_100mv,ddr2_vol/2_150mv)

 

DDR2 Channel B Ref Voltage (auto, ddr2_vol/2, ddr2_vol/2-100mv,ddr2_vol/2_50mv,ddr2_vol/2_100mv,ddr2_vol/2_150mv)

 

So many voltages, not sure which one to mess with, so that's why I came here. To see if anyone else is using the Asus Crosshair and this memory. This has to be the most tweakble bios I've seen and to be honest, confuses me a little.

 

I am glad I went with 4gig of Ram, Vista is quite the RAM sucker. Turned off the AERO feature since it appears to be such a memory hog. Trying to get this system as efficient as possible for gaming, I got some 3dmark06 scores of 8971 which seems low for this system setup (but it could be vista versus xp2, don't know).

 

Thanks for any assistance in advance.

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You are already quite lucky to make stable with all four DRAM banks populated at the full speed without overclocking. If you want to take the chance and lower the timings of the DRAM then you can use the below settings. Keep in mind, that the timings of 4-4-4-12 and the bandwidth of 800Mhz applies to 2 sticks, not 4 sticks so I reiterate, if you are stable with 4 X 1024 of 6400C4 at 5-5-5-18 and "Auto" settings, then you would do well to just stay there.

 

Download Memtest from http://www.memtest.org and extract the ISO image. Burn the ISO image to an CD-ROM disk.

 

If you want to try it, these are the settings:

 

DDR2 Voltage Control = 2.1V

North Bridge Voltage: 1.55v

South Bridge Voltage: Auto

South Bridge PLL: Auto

DDR2 Controller Ref Voltage: Auto

DDR2 Channel A Ref Voltage: Auto

DDR2 Channel B Ref Voltage: Auto

 

Memory Timing

 

SLI-Ready Memory: Disabled

tCL: 4

tRCD: 4

tRP: 4

tRAS: 12

Width of DRAM Interface: 64-bit

1T/2T Memory Timing: 2T

 

Set to these timings. Boot to the optical drive with the memtest disk and allow for two full passes.

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Thanks for tips. The machine is running fine, it just seems I could be getting something more out of it. For all that gear, I'm only getting 3dMarks o f 8971. I'll give your ideas some thought, but might let my machine "burn in" for a bit first.
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Yes, your issue is that you are expecting Core 2 results from AMD. It's just not possible. With a Core2 @ 3.4Ghz and an 8800GTS 320 at 600/2000 I was getting ~12000 3DMark06 points. When set to 2.4GHz (Stock E6600) and a stock 8800GTS I was getting ~10000 3DMark06 Points.

 

If you are not overclocking your CPU or GPU, then ~9000 3DMark06 points is fair. I bet if you clocked up to 3.4 on the CPU and 600/2000 on the GPU you would be far higher.

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I just need to figure out how to safely do all that. I've tried using the AI overclock on the board and took it to 8%, it told me my DDR2 and Term voltages were a bit over the threshold given by the board. So I decided to take it back down to 5% to be safe, even though the system was acting just fine.

 

Asus PC Probe II sets a DDR2 Term voltage of .90 Nominal with a 10% Threshold (it's currently running at .96). It sets the DDR2 voltage to 1.80 Nominal with a 10% Threshold (it's currently running at 1.94).

 

Not sure what that means or what the memory can really take. Just as a side note, I haven't touched any of the memory settings yet. The system is still setting it at 5-5-5-18 800mhz for the 4 sticks.

 

If anyone can send me to a OC'ing for dummies site, that would be great. Like I said, I'm sure I can get more out of this system than what stock setting are doing.

 

Thanks again for the help and advice in advance.

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Download memtest from http://www.memtest.org and extract the ISO image. Burn the ISO image to an CD-ROM disk.

 

Then restart the system, enter your BIOS Setup Utility and set to these values:

 

AI Tuning - Manual

Overclock Options Enabled

 

Overclocking

 

CPU Frequency: 215Mhz

CPU Multiplier: 15

Memory Clock Frequency: 800Mhz

PCIEX16_1 Clock: 100Mhz

PCIEX16_2 Clock: 100Mhz

CPU<->NB HT Speed: 5 X CPU Frequency (1000Mhz)

NB to SB HT Frequency: 200Mhz

NB --> SB HT SPeed: 5XNB to SB HT Frequency

CPU<--> NB HT Width: ? 16 ?16

CPU Voltage Range: Auto

CPU Voltage: Auto

DDR2 Voltage Control: 1.9v

HT Link Voltage: Auto

North Bridge Voltage: 1.55v

South Bridge Voltage: Auto

South Bridge PLL: Auto

DDR2 Controller Ref Voltage: Auto

DDR2 Channel A Ref Voltage: Auto

DDR2 Channel B Ref Voltage: Auto

 

Memory Timing

 

SLI-Ready Memory: Disabled

tCL: 4

tRCD: 4

tRP: 4

tRAS: 12

Width of DRAM Interface: 64-bit

1T/2T Memory Timing: 2T (test with Memtest. If stable, set to 1T and retest for stability)

Channel A Clock Skew: Normal

 

Advanced Memory Settings

tRC: Auto

tWR: Auto

tRRD: Auto

tRWT: Auto

tWTR: Auto

tRTP: Auto

tWRRD: Auto

tWRWR: Auto

tRDRD: Auto

tREF: Auto

tRFC: Auto

DRAM Termination: Auto

Max Async Latency: Auto

R/W Que Bypass: Auto

Dynamic Idle Cycle Counter: Auto

Idle Cycle Limit: Auto

DCQ Bypass Maximum: Auto

DRAM Burst Length: 8 (QW)

Dram Bank Interleaving: 4-Bank

Set all else to Auto

 

Boot to the optical drive with the memtest disk and allow for two full passes.

 

Results?

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  • 2 weeks later...

Slightly off topic, but the AMD Athlon 64 x2 6000+ does not run DDR2-800 (PC2-6400) memory at its full DDR2-800 speed. This is due to the fact that the Socket AM2 memory controller does not run its clock independently of the processor; instead, it runs at a set fraction (where the fraction's numerator is always 1 and the denominator is always an integer value, as in 1/8 or 1/11) of the processor's actual core clock speed. And 400MHz (the actual clock speed of DDR2-800 memory) does not divide evenly into 3000MHz (3GHz); dividing 400 into 3000 would equal 7.5. And the Socket AM2 memory controller can only use integer values for memory clock multipliers (e.g. it can use 7 or 8, but not 7.5) -- but using a multiplier of 7 would result in an out-of-spec memory bandwidth of DDR2-857 (PC2-6857). Thus, the multiplier value of 8 had to be used, with the result being that the Athlon 64 x2 6000+ runs DDR2-800 memory at only DDR2-750 (PC2-6000) speed even though the BIOS states that the memory is set for DDR2-800 operation. (And the 6000+ always runs DDR2-800 memory at DDR2-750 speed regardless of the number of modules installed.)

 

The only Athlon 64 processors which can run DDR2-800 memory at its full DDR2-800 speed are those processor models which are clocked at multiples of 400MHz (e.g. the 2.0GHz Athlon 64 x2 3800+; the 2.8GHz Athlon 64 x2 5600+).

 

Maybe that's why you were able to run four sticks of double-ranked memory at a marked DDR2-800 setting.

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Correct.

 

This is the difference between Intel's FSB and AMD's HTT. Motherboards call the AMD HTT the FSB to make it easier to understand in the overclock but really they are not the same as the memory controller is integrated into AMD 64 X2 CPUs and the memory speed is not based on a FSB but a ratio of the CPU HT (said as FSB but really is the HTT Frequency)/Multiplier. Your CPU speed - FSB/HT Mhz / Multiplier. The locked-in divider, makes the memory run at a set fraction of the CPU speed.

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Correct.

 

This is the difference between Intel's FSB and AMD's HTT. Motherboards call the AMD HTT the FSB to make it easier to understand in the overclock but really they are not the same as the memory controller is integrated into AMD 64 X2 CPUs and the memory speed is not based on a FSB but a ratio of the CPU HT (said as FSB but really is the HTT Frequency)/Multiplier. Your CPU speed - FSB/HT Mhz / Multiplier. The locked-in divider, makes the memory run at a set fraction of the CPU speed.

 

And that wasn't the first time that AMD's integrated memory controller has locked in a set divider. Its Socket 754 and 939 predecessors also came with this caveat, with the result of running DDR333 memory with a 2.4GHz processor resulted in the memory actually running at DDR320 instead of DDR333.

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