jgstew Posted January 13, 2006 Share Posted January 13, 2006 I have an ABIT-IC7 dual-channel motherboard, and 2xCMX256A-3200C2PT in dual channel configuration, which works flawlessly. I recently added VS1GBKIT400 so that the two 512mb sticks would be in a matched pair dual channel configuration along side the 2xCMX256A-3200C2PT. Memtest86+ revealed no errors. WindowsXP booted fine, and showed all 4 sticks running and at VS1GBKIT400's slightly slower latency. Everything seemed to work OK, but I turned of the hard drive virtual memory page file, and loaded up the ram, I got memory read errors and strange behavior of my system. I have since removed the 2xCMX256A-3200C2PT and have been running fine ever since. Do all 4 sticks need to be matched for everything to run ok? or should there be a way to have all 4 of what i have in 2 different sets of matched pairs? or are my errors due to turning off the page file? (i assume if i turn it back on and try loading up the memory in the same way i will get the same errors, but i dont know) Link to comment Share on other sites More sharing options...
Corsair Employee RAM GUY Posted January 14, 2006 Corsair Employee Share Posted January 14, 2006 Yes all four modules should be exactly matched for best performance. Link to comment Share on other sites More sharing options...
jgstew Posted January 14, 2006 Author Share Posted January 14, 2006 But shouldnt it run ok with all 4 in that are made up of 2 different matched pairs? why would this cause problems? i understand that best performance might be achieved having all 4 being match, but i dont understand why this MUST be the case. Does windows just not like the ram getting filled up or something? I'm not getting an out of resources error, im getting a memory read error, so thats entirely different. Link to comment Share on other sites More sharing options...
RJLeong65 Posted January 14, 2006 Share Posted January 14, 2006 But shouldnt it run ok with all 4 in that are made up of 2 different matched pairs? why would this cause problems? i understand that best performance might be achieved having all 4 being match, but i dont understand why this MUST be the case. It's just that modern memory controllers tend to be allergic to memory mixing. You'll never know what you'll get when you mix different pairs of modules: Sometimes, the memory will default to fail-safe settings; other times, the system will refuse to even POST at all. Does windows just not like the ram getting filled up or something? I'm not getting an out of resources error, im getting a memory read error, so thats entirely different. Actually, the RAM getting filled up (or more specifically, having all of the motherboard's memory slots filled with double-sided modules) will cause problems with all DDR400 memory controllers. The memory clockspeed will default to 166MHz (DDR333/PC2700). On an Intel platform like yours, the reduced memory bandwidth will result in a slight drop in overall system performance. By the way, you actually had six lines of memory installed in your PC. The CMX256A-3200C2 modules are single-sided, while all of Corsair's 512MB DDR400 modules are double-sided. In your case, if you want 1.5GB, the best match would be a TWINX1024-3200C2 kit with the modules of exactly the same revision and a close-enough lot number as your CMX256A modules. (The i875P chipset does support up to 6 rows of memory at full DDR400/PC3200 speed.) However, the Intel chipset-based systems may experience reduced performance with unevenly-loaded memory slots (a mix of single- and double-sided modules), so I'd recommend going with one TWINX2048 kit instead of trying to run with a mix of TWINX1024 and TWINX512 kits. As a general rule, Intel's DDR400 systems tend to deliver their best performance for a given amount of memory with only four rows of memory installed. (This means that your system will perform best with four single-sided modules or two double-sided modules.) Link to comment Share on other sites More sharing options...
jgstew Posted January 15, 2006 Author Share Posted January 15, 2006 This clears up alot in how DDR memory & the controllers work. I definately understand the benefit of having the higher end memory. What I still dont entirely understand is why i would get memory read errors when i open enough programs to fill the ram up close to capacity. (when i had 1.5gb) Is this because perhaps my ram was running at DDR400 speeds but trying to address more lines of memory than my controller was capable of ? AND... Is there any reason windows would be having troubles because of turning off virtual memory? I assume if you have enough ram, there's no need. I wasnt doing any gaming or anything that would take up a large amount of ram itself. and i also assume if you have more than enough ram for your needs, then it would be better to have the virtual memory off, and not have the hard drive being accessed unnessiarily. Again, thanks for the explinations. Link to comment Share on other sites More sharing options...
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