Rod_C

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Hi
I’m looking at buying a Q6600(G0 with intent to overclock) + Gigabyte GA-X38-DS5 + 4GB of DDR2 800
And I have been wondering what sort of difference there is between CAS5 and CAS6 ram (Performance wise). Dose having tighter timings help overclocking at all??
 

cyberjock

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Before I give you a little info to help you decide if you care about CAS, I have to ask this:

Where the hell did you see CAS6 memory? I don't think I've ever seen it for sale anywhere I've been!

Ok, now for the facts :).

Tom's did an article comparing CAS to Mhz rating of RAM. Clearly if you buy CAS 4 ram, and set it to CAS 5 you can increase the RAM speed because you are adding a delay. Timings versus Mhz rating is a hot topic that is debated on many levels and with varying opinions. My personal thoughts are to buy good low CAS memory and run it at the designed speed you want. If you intend to use DDR2-1066, just buy DDR2-1066 or buy DDR-800 and overclock it adding in a CAS to make up the difference. On the other hand if you intend to overclock this machine to the limits, you want to buy the highest Mhz rating with the lowest CAS(effectively buying "higher quality" RAM) giving you a higher likelyhood of overclocking. Big picture the difference between CAS5 and 6 is about 2% performance if I remember correctly.

Read this article for some more info:
http://www.tomshardware.com/2006/03/31/tight_timings_vs_high_clock_frequencies/

Hope this helps.
 

MrCommunistGen

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Your link didn't take me to a page with memory on it... from the sound of it though you're looking at DDR3 which doesn't really have a performance advantage over DDR2 especially for the price. You can get a 2GB kit of 800MHz CAS4 DDR2 for about $85.

-mcg
 

ausch30

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There is some cas 6 out there like here http://www.newegg.com/Product/Product.aspx?Item=N82E16820231112

The other's are correct, The Q6600 runs at FSB1066 and your goal when overclocking it should be around FSB1600 so getting a low latency DDR2800 would be your best option like this.
http://www.newegg.com/Product/Product.aspx?Item=N82E16820231122

or this

http://www.newegg.com/Product/Product.aspx?Item=N82E16820211188


I listed 2x2gb sets because you stated that you wanted 4gb. You can either go with 2x2gb or 4x1gb. If you go with the 4x1gb you can get memory for less money and with better timings like this
http://www.newegg.com/Product/Product.aspx?Item=N82E16820220144

or this

http://www.newegg.com/Product/Product.aspx?Item=N82E16820146565

but you loose the ability to add more later because you'll fill all your slots.
 

Fionivar

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Corsair 800MHz DDR2 (TWIN2X2048-6400CX4) - CAS 4-4-4-12

This would be the best choice for you in the long run. Much more stable RAM than many of its competitors, and handles overvoltage great. If you plan to overclock, the lower the CAS the better.

Oh - and CAS6? Where did you find that?