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RAM with different frequency & dual channel question

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October 13, 2010 12:08:46 AM

Hello,

I found a very good price for a 2X1GB set but they're 667 instead of the 1066 set i own... If i put RAM with different frequency in a channel (slot A & C for example, channel 1), they'll work in Single channel mode, right? Could channel 1 be 1066 and channel 2 be 677, at same time? Or will the 1066 sticks run at 667? If so, how exactly will i feel that lowered RAM speed during use of the computer? Hope to get fast answer or it'll be sold to someone else! :whistle: 

Thanks.
a b } Memory
October 13, 2010 1:21:43 AM

Any time you mix RAM, just know that your computer will operate at the lowest frequency (in this case 667) across all DIMM slots, regardless of placement. Furthermore, the highest voltage will have to be used. This is because the manufacturer has tested the RAM stick(s) and determined the optimal settings prior to selling, thus they mark the optimal settings on the stickers. Lastly, the latency must be configured to the higher values. This is similar to the voltage, in that the RAM sticks will become unstable.

So, let's take your 667 and 1066 sticks and put some perspective on your question. Take this for example:

(This is purely hypothetical, as I have no idea what your specs really are)

2 x 1GB @ 667 DDR2 5-5-5-18 1.8V

2 x 1GB @ 1066 DDR2 6-6-6-20 2.1v

If you were to use these two kits, you would be best off manually configuring your BIOS to

1. 667
2. 2.1V
3. 6-6-6-20

You must also find out if the 667 kit can operate at the higher voltage without frying them.
October 13, 2010 1:46:17 AM

What i have is G.SKILL PK SERIES (seems to be 2v) and what i can buy now are basic KINGSTON (seems to be 1.8v) both CL5. If i buy them together and let the BIOS together, wouldn't it lower the G.SKILL by itself? Anyway, what about the performance loss from 1066 to 667?
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a b } Memory
October 13, 2010 1:55:38 AM

If you have made no manual adjustments to your BIOS, then all of your DRAM settings are on [Auto]. With everything on [Auto], the BIOS will automatically drop your 1066 to 667, but your latency and voltage will not configure themselves. The voltage will throttle, meaning it will increase when needed, and decrease when the need for more power has subsided. Latency will likely be auto configured to a default DDRX (where X = your gen. I assume DDR2 because of the frequencies in question).

So let's pretend you've done your research and found that these two kits will play nicely together. You will not see a performance hit. In terms of gaming, maybe a 1-2 fps reduction. This is because lower latencies are more important than higher frequencies.

October 13, 2010 2:21:28 AM

I don't do much gaming, i just thought they might be slower to process, but i don't know how much... From your words, sounds like nothing! I didn't find anyone using a G.SKILL + Kingston couple sadly...
a b } Memory
October 13, 2010 9:58:14 AM

T_T said:
Any time you mix RAM, just know that your computer will operate at the lowest frequency (in this case 667) across all DIMM slots, regardless of placement. Furthermore, the highest voltage will have to be used. This is because the manufacturer has tested the RAM stick(s) and determined the optimal settings prior to selling, thus they mark the optimal settings on the stickers. Lastly, the latency must be configured to the higher values. This is similar to the voltage, in that the RAM sticks will become unstable.

So, let's take your 667 and 1066 sticks and put some perspective on your question. Take this for example:

(This is purely hypothetical, as I have no idea what your specs really are)

2 x 1GB @ 667 DDR2 5-5-5-18 1.8V

2 x 1GB @ 1066 DDR2 6-6-6-20 2.1v

If you were to use these two kits, you would be best off manually configuring your BIOS to

1. 667
2. 2.1V
3. 6-6-6-20

You must also find out if the 667 kit can operate at the higher voltage without frying them.


^++1
Same thinking here. Well, if you want to mix RAM make sure it's the same speed and timing for best result. Like me in my rig, when I used A-Data alone I can go 4-4-4-11 @1.8V. But Hynix cannot go 4-4-4-11, only 5-5-5-12 @1.8V.
So I run both of them at worst scenario, 5-5-5-12@1.8V.
October 13, 2010 2:15:58 PM

Concerning this advice above:

> 1. 667
> 2. 2.1V
> 3. 6-6-6-20


This 1066 RAM is probably overclocked DDR2-800:

2 x 1GB @ 1066 DDR2 6-6-6-20 2.1v

And, generally DDR2-800 runs at 1.8 V;
thus, DDR2-1066 should run OK at 800 MHz and 1.8V.


Also, your DDR2-667 may not like 2.1V:
contact the manufacturer to be sure,
repeating:

> You must also find out if the 667 kit can operate at the higher voltage without frying them.


We run Corsair CM2X2048-8500C5D at 800 MHz and 1.8V
in our ASUS P5W64 WS Professional motherboard,
and it's very stable.

The EPP #1 timing in its SPD calls for 2.1V at 533 MHz DRAM Frequency
and 1.8V at 400 MHz DRAM Frequency (using CPU-Z nomenclature).


I hope this helps.


MRFS
October 15, 2010 12:22:33 AM

I'm not so familiar with these things but to be short, if i put them with my G.SKILL set, the BIOS should adapt since it's in auto mode, therefore no worries. Right? I will do that.
a b } Memory
October 15, 2010 2:27:25 AM

Auto setting, ... can sometimes causes system instability. But you can try first. Just remind that if it crashes, you have to set it manually.
!