andygizzle Posted October 31, 2007 Share Posted October 31, 2007 Hello. I am currently running 2x1024 Twin2x 6400C4D (at 2,1V, 800mhz, 4-4-4-12) on Asus P5N32-e sli motherboard (not the Plus edt.). FSB is running 9x1333mhz (3GHz) on Intel C2D E6600. I want to upgrade to 4GB, but can't seem to find this memory for sale any more. I only find 6400C4DHX. I see those have the colour gray. The questions are: can I install another 2GBs of C4DHX and run everything smooth? Are there any differenses at all between these two modules? In advance, thanks a lot :-) Link to comment Share on other sites More sharing options...
tonyblerone Posted October 31, 2007 Share Posted October 31, 2007 Hi Andy, I have the C4DHX and the only difference between these and the C4Ds as far as I'm aware is that the DHXs have a better heat sink which keeps them cooler when overclocking. (I didn't buy mine to overclock, it was simply because the C4D modules weren't available and I'm impatient...) But to be sure, I would get confirmation from a Corsair rep. Link to comment Share on other sites More sharing options...
DerekT Posted October 31, 2007 Share Posted October 31, 2007 Hello. I am currently running 2x1024 Twin2x 6400C4D (at 2,1V, 800mhz, 4-4-4-12) on Asus P5N32-e sli motherboard (not the Plus edt.). FSB is running 9x1333mhz (3GHz) on Intel C2D E6600. I want to upgrade to 4GB, but can't seem to find this memory for sale any more. I only find 6400C4DHX. I see those have the colour gray. The questions are: can I install another 2GBs of C4DHX and run everything smooth? Are there any differenses at all between these two modules? 6400C4 and the 6400C4DHX are identical except for the heat spreaders. Keep in mind that if you run with all four DRAM banks filled, you will very likely have to drop the bandwith from 800Mhz to 667Mhz. This is because the on motherboard memory controller can not keep up with the extra DRAM at the rated 6400 speed. You will very likely need to drop the speed of the DRAM from 800Mhz to 667Mhz. If you populated 4 X 1024MB of PC8500 (1066Mhz) DRAM, then you would very likely have to drop to PC6400 (800MHz) DRAM, etc. 2 X 2048 will not issue this problem. This is a problem of all 4 banks being populated. Think of it this way. If you have a small phone book, then when you go into the index to find the page where you will find the phone number you are doing so at a certain speed due to the pages of the Index. Then you have to drive through the pages to get to the number. Now if your index is twice as large and the pages twice as many, then it takes longer to access the data. Now DRAM has a Strobe and the length of the strobe is how long the rows and columns can be left open before they must be refreshed. There is not enough time for the dram to be refreshed and then accessed with 4GB at the full access speed of the DRAM. The chipsets are optimized for 2GB, not 4GB and for 2 DRAM slots, not 4 DRAM slots populated. You can overclock the FSB (and hence the Memory Controller Hub = MCH) to gain some extra bandwidth and thus access the capabilities of the DRAM since the chipset is now clocked up. Usually when you clock up the FSB and concurrently the Memory Controller Hub (MCH) you need to raise the voltages of the CPU/MCH a bit as well. There are exceptions. Some are lucky and are able to run at full bandwidth speed, but they are the exception rather than the rule. You should know this before you make any decisions. Also be clear that some boards will not work at all with 4 DRAM banks populated. These are few but they are there. Then RMA of the mainboard will be necessary. Keep in mind that this limitation is of the board chipset, not the memory. My advice? Sell the two sticks and purchase 2 X 2048 6400C5DHX and forestall the possibility of any problems. With the drop in DRAM prices, this is the best move in my opinion. Link to comment Share on other sites More sharing options...
andygizzle Posted October 31, 2007 Author Share Posted October 31, 2007 Thanks for the reply guys. Ok, so the best solution would be to buy 2x2048 sticks. I don't need them yet, strictly speaking, so I may wait till I do. Again, thanks :-) Link to comment Share on other sites More sharing options...
Corsair Employees RAM GUY Posted October 31, 2007 Corsair Employees Share Posted October 31, 2007 Yes just buy them all at the same time so they match and with 4 modules you will be limited to DDR667 with that MB. Link to comment Share on other sites More sharing options...
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