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Mixing RAM 2x2gb + 2x4gb

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  • Memory
  • DDR2
  • Latency
  • RAM
Last response: in Memory
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February 18, 2010 11:43:50 AM

I want to add 2x4gb ram to my existing pair of 2x2gb ram. The original ram is OCZ 2x2gb DDR2 800MHz Titanium CL4(4-4-4-15). The RAM I'm looking at adding is Geil and is also DDR2 800mhz. However it's latency figures are different at CL6 (6-6-6-18). Can anyone tell me if I would have compatibility problems and what the result of running pairs of RAM with different latency / voltage / brands is please? I'd stress that the DDR2 RAM will be in matched pairs and that I'm running under 64bit Vista

More about : mixing ram 2x2gb 2x4gb

a c 128 } Memory
February 18, 2010 12:26:50 PM

First, check the board manual to see if mixing 2gb sticks with 4 gb sticks is possible; different configurations should be listed in the memory section. Then, check the voltage spec of both pairs and see what the bios is using now. For example, my biostar bios uses 1.95 as the lowest ram voltage, even though some brands run fine at 1.8 volts. Then try the default settings; if you get bluescreens, you'll have to experiment with different voltages from 1.8 to the max recommended for your old or new pair.
February 18, 2010 1:17:41 PM

Thanks for your reply o1die. My board, Asus P5Q SE/R, does support a configuration of the matched paie of 2gb sticks and the matched pair of 4gb sticks. What I don't know is if it will support them being at different latencies / voltages. I've not bought the 8gb set as yet as I'm trying to find out what will happen before I do so. My manual says that I shouldn't mix sticks of different latencies but I'm not sure if that means as a pair, in the same coloured sockets, or in any configuration. Can you tell me if there is a link between latency and voltage. Would I be correct in thinking that increasing voltage lowers latency for example?
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a c 128 } Memory
February 18, 2010 3:50:04 PM

Your ram brands should be adequate quality wise; you can change the timings in manual mode to the higher numerical listings of the new ram or check the motherboard default settings if you get bluescreens. The higher values are actually slower, but you want stability, so give it a try if you have any problems.
February 18, 2010 4:32:43 PM

I've been checking out the voltage requirements for the different makes. My existing ocz runs at 2.2v giving the CL4 spec. there is no lower spec given. The geil runs at 1.8v to achieve CL5 or 6 and 2v for CL4. Do you know what would happen if I ran the geil at 2.2v? Would that be OK? Do you think the ocz would run OK at a lower voltage?

I looked at the crucial sight and they recommended an 8gb kit 2x4 with a cl of 5 at 1.8v as being compatible. I'm thinking that for that to be so either the ocz has to run at a lower voltage and higher latency or the crucial runs vice versa.

If I change the Cl for the ocz, as you suggest, will that lower the voltage that the it needs? I t6hink I'll try that and see what haqppens.
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