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Another question about mixing RAM

  • Memory
  • RAM
Last response: in Memory
July 28, 2011 7:55:28 PM

I posted on OCN as well so if you're on that forum this will look familiar. Just learning and getting my education from a couple different sources.

I have read through a lot of the posts on incompatible RAM but my question may be a bit more specific.

I built my system on the cheap as I was given the MOBO and OCZ RAM by a friend.
The OCZ Reaper RAM is 4 GB (2X2gb) PC2 8500 1066MHz Rev 3. at 5-5-5-18 2.1 - 2.3 v.

I found 4 GB (2X2gb) Mushkin Blackline Enhanced PC2 8500 1066MHz at 5-5-5-15 2.0 - 2.1 v for sale really cheap.
The specs are so close I couldn't pass it by for $50 to bring me up to 8GB of quality memory.

It's working fine in my system but I was wondering if I should tweak the Bios to get the tRAS on the Mushkin to 15, same as the OCZ.
Also, how do I verify that my motherboard is applying the correct voltage to the DIMMs? And, should I manually set the voltage to 2.1 if the memory is working OK?

I have installed CPU-Z but I'm just learning all of this so also looking for advice. It looks like the memory is currently running at 800 MHz.

I'm not looking for amazing benchmarks; just good real-world performance for gaming.

Thanks in advance.

More about : question mixing ram

a c 347 } Memory
July 28, 2011 8:30:06 PM

1066MHz 5-5-5-18 2.1 - 2.3 v
1066MHz 5-5-5-15 2.0 - 2.1 v
1066MHz 5-5-5-18 2.1 v

The differences between 15 and 18 tRAS is minimal so IMO run them together at 18. There's nothing worst than gaming for a 'period' of time and getting a BSOD.

Installing, in most cases stagger them: | New | Old | New | Old | meaning the blended is better per each channel; assuming | Ch0 | Ch1 | Ch0 | Ch1 |.

Since I don't see you MOBO list a generic response; BIOS: DRAM Voltage -> 2.10v also set the DRAM Frequency -> DDR 1066MHz, and ALL of the CAS Timings {5-5-5-18}.
July 28, 2011 9:37:11 PM

Thanks for the reply. My MOBO is Gigabyte GA-MA770-UD3. I think you see the specs at [More information]>[Member configuration] under the avatar. Maybe not; I'm new to the forum.

Regarding "staggering": I thought DDR2 ran in pairs so they need to reside in matched slots?
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a c 347 } Memory
July 28, 2011 10:03:21 PM

Your MOBO uses an older channel scheme, most 'today' are as shown below; IF you have them | Old | Old | New | New | then you did stagger them ;) 

Most Newcomers don't list their I didn't look.

Channel 0: DDR2_1, DDR2_3
Channel 1: DDR2_2, DDR2_4
CPU: | DDR2_1 0 | DDR2_2 1 | DDR2_3 0 | DDR2_4 1 |
So in your case -> | New 0 | New 1 | Old 0 | Old 1 | or visa versa

Set Memory Clock -> 5.33 {5.33 x 200 MHz FSB = 1066 MHz}
DDRII Timing Items -> Manual
CAS# latency -> 5
RAS to CAS R/W Delay -> 5
Row Precharge Time -> 5
Minimum RAS Active Time -> 18
DRAM Voltage Control -> 2.10v

Save & Exit


Most now:
July 29, 2011 3:25:30 AM

So, I have the timings set at 5-5-5-18 but I'm just not sure how to change the voltage on my motherboard.
In the BIOS, the DDR2 Voltage Control has the following options:
NORMAL, +0.025v, +0.025v.........up to +0.275v. These appear to incremental adjustments.
It's currently set to [NORMAL] and boots OK. The PC Health shows 1.920v but that's from within the BIOS so I don't know if that adjusts per usage after a full boot.
Does CPU-Z show the voltage of the DIMMs? The SPD tab has the timings table but I'm not sure if there is a place in the program that shows the operating voltage like it does on the CPU tab.

Should I just leave it at NORMAL since it boots OK?

Also, I haven't been able to get the RAM to boot at 1066. The memory clock settings are either AUTO or MANUAL with MANUAL having settings of:
x2.00 x2.66 x3.33 x4.00 x5.33. When I attempt x5.33 to get to 1066, the system doesn't get to the motherboard splash screen (is this what others mean by "won't post"?). Then, I have to clear the CMOS to get a boot.

As you can tell, I'm a noob at this and appreciate the suggestions and tutoring!

Here are screen shots of CPU-Z:

a c 347 } Memory
July 29, 2011 1:18:17 PM

I know your CPU can support 1066 MHz RAM, and I see no notations where a FSB OC is required. So try the higher DRAM Voltage as listed below in conjunction with the 5.33 Memory Multiplier. Keep in mind you do have a 'mixing' issue so there's no guarantees that 1066 MHz will work - if it does not then keep it at 800 MHz the difference is at most 1%~2% and you couldn't 'feel' the difference.

In addition, I ran across a G.SKILL post where HT & NB Voltage were raised to aid in the problem -> ; don't touch your CAS Timings.

4 x 1.8V DDR2 DIMM sockets supporting up to 16 GB of system memory (Note2)
Dual channel memory architecture
Support for DDR2 1333(OC)/1066(Note 3)/800/667 MHz memory modules
Support ECC memory (Note 4)

(Note 3) Whether 1066 MHz or above memory speed is supported depends on the CPU being used.

First the DRAM Voltage:
DRAM Voltage Control -> 2.10v {+0.30v}
1.80v -

BIOS, make certain that you have BIOS versions
MOBO v 2.1 = FG
MOBO v 2.0 = FF
MOBO v 1.0 = F9G

AMD Phenom II X4 965 3400MHz 512KBx4 6MB Deneb 45nm C3 125W 4000 FG/FF/F9G
AMD Phenom II X4 965 3400MHz 512KBx4 6MB Deneb 45nm C2 140W 4000 N/A

Good Luck!