johnno Posted November 19, 2007 Share Posted November 19, 2007 Hello, TWIN2X1024A-6400 and TWIN2X2048-6400 together. Giving me a total of 3gb. Thanks Link to comment Share on other sites More sharing options...
Corsair Employees RAM GUY Posted November 20, 2007 Corsair Employees Share Posted November 20, 2007 They should be but with 4 modules on the MB you have listed DDR667 would be suggested. Link to comment Share on other sites More sharing options...
johnno Posted November 20, 2007 Author Share Posted November 20, 2007 Hi, thanks for your reply. I'm just wondering why it could be better to run it at 667? Link to comment Share on other sites More sharing options...
DerekT Posted November 20, 2007 Share Posted November 20, 2007 The on motherboard (MCH/Northbridge) Memory Controller can not keep up with the extra DRAM at the rated speed. You will need to drop the speed of the DRAM from 800Mhz to 667Mhz. If you had purchased 4 X 1024MB of PC8500 (1066Mhz) DRAM, then you would have had 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 and relates to both Nvidia and Intel chipsets. When you populate two more banks of DRAM, the controller now needs to access and store twice the length. You are then asking it to do it at the speed that it did it with two banks 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. As well, they SHOULD work together. This does not mean that they WILL work together. You can NOT expect to mix and match DRAM to stability. It might work, it might not and certainly you will have to be kind to your motherboard memory controller to possibly get this to work. It's always a dice throw when one does what you are talking about. Link to comment Share on other sites More sharing options...
johnno Posted November 20, 2007 Author Share Posted November 20, 2007 Hi, thanks for the great reply. :): I currently have 4 x 512mb running at default speed, and these seem to be fine. I have not run into any issues yet. The reason for the original question is that I was wondering if it would be worth upgrading from 2gig to 3gig? I currently have XP MCE 2005 installed and was thinking about upgrading to Vista HP 32 bit. I really want to get the best out of games like Crysis and UT3. Thanks again Link to comment Share on other sites More sharing options...
DerekT Posted November 20, 2007 Share Posted November 20, 2007 4 X 512 is far easier than 4 X 1024 so you might get away with it. Be clear though, you may find issues arise in time. Blue screens, crashes, etc and finally you might find physically damaged DRAM. I personally would drop the throughput and forestall this possibility. Now that you know, you are informed and the decision is yours. I work in the industry and I see the return rates of those who run with 4 DRAM banks and full bore. Both with Intel and Nvidia. You might also have problems with 2 X 1024 and 2 X 512. Certainly the possibility of issues arise as you maximize the DRAM capacity and DRAM banks population. Again, often this issue is longer term, cumulative and degenerative. Good luck... Link to comment Share on other sites More sharing options...
johnno Posted November 20, 2007 Author Share Posted November 20, 2007 Many thanks again for your very informative replies. Link to comment Share on other sites More sharing options...
DerekT Posted November 20, 2007 Share Posted November 20, 2007 You're very welcome, and I wish you luck with your system choices, whatever they may be. Link to comment Share on other sites More sharing options...
Corsair Employees RAM GUY Posted November 20, 2007 Corsair Employees Share Posted November 20, 2007 NP Please let us know if you have any more questions! Link to comment Share on other sites More sharing options...
johnno Posted November 21, 2007 Author Share Posted November 21, 2007 No more, thanks. I think i'll leave the 4 x 512 as they are. It has been 100% stable at stock and when I had a x2 3800+ @ 2.6. It may be because my board currently has the ram running at 376.6MHz, 5,5,5,15, 2T. Iirc when i had the 3800 the ram was at 400+ and was still fine. Link to comment Share on other sites More sharing options...
Corsair Employees RAM GUY Posted November 21, 2007 Corsair Employees Share Posted November 21, 2007 NP Thank you for letting me know! Link to comment Share on other sites More sharing options...
bickmade Posted December 13, 2007 Share Posted December 13, 2007 4 X 512 is far easier than 4 X 1024 so you might get away with it. Be clear though, you may find issues arise in time. Blue screens, crashes, etc and finally you might find physically damaged DRAM. I personally would drop the throughput and forestall this possibility. Now that you know, you are informed and the decision is yours. I work in the industry and I see the return rates of those who run with 4 DRAM banks and full bore. Both with Intel and Nvidia. You might also have problems with 2 X 1024 and 2 X 512. Certainly the possibility of issues arise as you maximize the DRAM capacity and DRAM banks population. Again, often this issue is longer term, cumulative and degenerative. Good luck... Hello, I'm in the same boat right now. I have 2x512 sticks that are DDR2 800 and I'm going to get another 2x512. Your recommending to down the speed to 667? Sorry for being ignorant, its getting late here. Link to comment Share on other sites More sharing options...
Corsair Employees RAM GUY Posted December 13, 2007 Corsair Employees Share Posted December 13, 2007 Yes with most MB's as you add more memory to them you may need to slow the memory down, that is normal. Link to comment Share on other sites More sharing options...
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