Mixing ram with different CAS latency and memory size

abcrwes

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Jan 4, 2013
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I have a asrock z77 pro 4 motherboard and have the G.Skill Sniper DDR3 8 GB (2 x 4 GB) PC RAM (F3-12800CL9D-8GBSR) RAM inserted in 2 of the 4 slots (1 & 3) available. I just about mistakenly thought that every modern ram would be compatible with a modern mother board - so I admit, without proper investigation I purchased a corsair vengeance Corsair Vengeance DDR3 8 GB (1 x 8 GB) PC RAM (CMZ8GX3M1A1600C10).

The differences I see between these 2 RAMs are in CAS latency - 9-9-9-24-2n vs 9-9-9-24 and Dual-Channel vs Quad-Channel.

Three questions:
1) Should I return the corsair vengeance RAM?
2) If not, Is Corsair Vengeance compatible with asrock z77 pro4? I do not see this RAM listed in asrock site.
3) If there is a way to workaround without returning it, what are the ideal bios settings to do in motherboard?

Thanks always for your responses.
 

sharkbyte5150

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Mar 22, 2012
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Return the Corsair and just get a 2nd set of the Sniper RAM that works, it's almost the same price.

Your motherboard memory specs say dual channel, so you need to buy dual channel kits and install in pairs, not a single quad channel module.

Mixing RAM is not the issue, because you can get two different brands with same latency, timing and voltages (important) but you have to get RAM that runs in dual channel if that's the specs of your motherboard. Also, your RAM will run at the speed of the slowest DIMM so match speed or you're wasting money.
 

abcrwes

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Jan 4, 2013
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Thanks for your reply! I went through the dual vs quad difference (Googling) and saw people say that a Quad Channel RAM should work fine in a dual-channel mother-board.

Regarding the speed and voltage, both are same (1600MHz and 1.5V).

I live in India and just figured out that, products can be returned only if they are defective :-( So I will probably try to do what best I can do with corsair vengeance (last option is to sell it via ebay).

Buying another corsair vengeance and inserting it in 4th slot - will it help?
 

sharkbyte5150

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Mar 22, 2012
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I don't think it's safe to say that in general Quad channel can run fine in dual channel slots.....I think if you buy a quad channel kit (4x4GB) it may run fine because some say a quad channel kit is no different than 2 dual channel kits.

However, my question is "why bother not buying RAM to match your motherboard specs?" You already saw that the Sniper dual channel works fine, so why not just get another set?

I have accidentally purchased quad channel RAM and tried to use it on a dual channel motherboard and it would not work, not on its own or mixed with a dual channel kit so I really think you should just sell that Corsair or try to return it and get another of the same set you already have.