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TWIN2X2048-8500C5D - not for 4GB?


Rambler358

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Just purchased a pair of TWIN2X2048-8500C5D RAM modules. In some limited reading here, I think I'm seeing that they can't be run @ 1066MHz with 4GB installed - is this correct?

 

I'm still in the return period of this RAM with Newegg, and if the above is true do I have any options for running 4GB of 1066MHz DDR2 RAM in my Dell XPS 630i - at the 1066MHz speed? Thanks in advance for any info.

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Just purchased a pair of TWIN2X2048-8500C5D RAM modules. In some limited reading here, I think I'm seeing that they can't be run @ 1066MHz with 4GB installed - is this correct?

 

I'm still in the return period of this RAM with Newegg, and if the above is true do I have any options for running 4GB of 1066MHz DDR2 RAM in my Dell XPS 630i - at the 1066MHz speed? Thanks in advance for any info.

 

Actually, you're better off with one TWIN2X4096-8500C5D(F) kit instead of two TWIN2X2048 kits if you really want 4GB. This is due to JEDEC standards restricting guaranteed memory support to one stick of memory per channel - and using four sticks of memory would result in two sticks installed per channel. Operation of DDR2 memory anywhere near its full rated speed with four slots filled is not guaranteed to be stable.

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Actually, you're better off with one TWIN2X4096-8500C5D(F) kit instead of two TWIN2X2048 kits if you really want 4GB. This is due to JEDEC standards restricting guaranteed memory support to one stick of memory per channel - and using four sticks of memory would result in two sticks installed per channel. Operation of DDR2 memory anywhere near its full rated speed with four slots filled is not guaranteed to be stable.

Thanks! So if I were to go with the 2 x 2GB route with 1066MHz rated RAM (4GB total), I should be able to get that speed and not have it revert back to 800MHz (in theory) - i.e. more stable than 4 x 1GB sticks?

 

EDIT: Or would I be better off getting 4GB of 800MHz RAM and overclocking it? And if I did go with 800MHz, would 2 x 2GB still be the better option? Thanks again.

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As far as i have experienced on this forum, it is always better to go with 2x2GB compared to 4x1GB. Simply because the memory controller handles it better.

Thanks! Now the $64k question - should I go for 1066MHz modules for the Q6600 CPU, or just stick with 800MHz for better reliability perhaps?

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Thanks! Now the $64k question - should I go for 1066MHz modules for the Q6600 CPU, or just stick with 800MHz for better reliability perhaps?

 

For non-overclocked I would go with the Twin2X4096-6400C5's and if you are going to overclock, then I would go with the Twin2X4096-8500C5's.

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For non-overclocked I would go with the Twin2X4096-6400C5's and if you are going to overclock, then I would go with the Twin2X4096-8500C5's.

 

I think you're wrong here. Q6600 works at 1066 (266FSB) if it's not overclocked, so it will utilize 8500C5's better (at 266x4=1066 or 533DDR), if you overclock it at 400FSB the 6400C5's (or C4's for a little more money) will work at 800MHZ (200x4=800 or 400DDR) better. However, for FSBs over 400MHZ 8500C5 is the choice. Good Luck.

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I think you're wrong here. Q6600 works at 1066 (266FSB) if it's not overclocked, so it will utilize 8500C5's better (at 266x4=1066 or 533DDR), if you overclock it at 400FSB the 6400C5's (or C4's for a little more money) will work at 800MHZ (200x4=800 or 400DDR) better. However, for FSBs over 400MHZ 8500C5 is the choice. Good Luck.

 

If you were speaking dual core rather than quad core I would agree with you. However, the CPU <--> DRAM ratio has another variable on a Quad Core that is not at all in the case of dual core, and this variable (characteristic) is very important when the CPU is bandwidth saturated. If you make use of a Quad Core, then there are times when the CPU is bandwidth saturated due to the lack of cache data sharing between the two sets of cores, thus leading to a multiplicity of identical data residing in both caches. This situation is helped along when the DRAM is running faster than the CPU.

 

For example, Core 1 and Core 2 share their cache data. Core 3 and Core 4 share their cache data. Core 1 and 2 do NOT share their cache data with Core 3 and Core 4. There are many times where multiple parallel instructions are sent to both sets of cores and of which the requests for the identical data must be sent to both shared caches as seen individually. This can lead to stalls and when the DRAM is running faster, this added bandwidth (that is mostly theoretical for Dual Cores) does make an added benefit to decrease stalls.

 

Thus, for the Quad Core and especially the Quad Core overclocked, the increase of DRAM speed will benefit.

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