Q: I just replaced my 2 512MB sticks for a 2GB stick....would it hurt to put in the other two 512MB as well? I have heard they all need to match...is this true? the two 512's are like 533 mhz, the 2 Gb is 667 I think. thanks for the help system specs as requested... System Security Status CIS Benchmark Score Unknown Available only for Windows 2000, XP Pro, and 2003 Virus Protection OK Up-to-date Microsoft Security Updates OK Up-to-date Computer Profile Summary Computer Name: Blackbird-pc (in WORKGROUP) Profile Date: Sunday, August 17, 2008 11:10:11 PM Advisor Version: 7.2x Windows Logon: Blackbird Operating System System Model Windows Vista Home Premium (build 6000) HP-Pavilion RK537AA-ABA a1723w System Serial Number: CNX6510T5F Enclosure Type: Desktop Processor a Main Circuit Board b 2.80 gigahertz Intel Pentium D 16 kilobyte primary memory cache 1024 kilobyte secondary memory cache Board: ASUSTek Computer INC. LEONITE 5.00 Serial Number: MS1C6CS03000671 Bus Clock: 200 megahertz BIOS: Phoenix Technologies, LTD 5.08 12/08/2006 Drives Memory Modules c,d2038 Megabytes Installed Memory Slot 'A0' has 2048 MB Slot 'A1' is Empty Slot 'A2' is Empty Slot 'A3' is Empty
A: Always install DIMMs with the same CAS latency. for optimum compatibility is is recommended that you obtain memory modules from the same vendor. You can install varying memory sizes in Channel A and Channel B. The system maps the total size of the lower-sized channel for the dual-channel configuration. Any excess memory from the higher-sized channel is then mapped for single-channel operation. A motherboard can usually handle up to three different different speeds, but all modules are reduced to the speed of the lowest module. So, keep that in mind. If you install four 1 GB memory modules, the system may detect less than 3 GB of total memory because of address space allocation for other critical function. This limitation applied to XP and Vista 32 bit version operating systems since it does not support PAE (Physical Address Extention) mode. Basically, this all means that it isn't a good idea to install the original modules unless they are from the same vendor as the new modules, but you can try and see if it will work. It can actually work for some time before an issue may arise. You could run your system for well over a year without any errors, or it could error out right away. If down the road your system enters a reboot loop, where it hits the Welcome Screen, shuts off, reboots, hits the Welcome Screen, shuts off, reboots, forever until you manually shut it off by holding in the power button, simply unplug your system and remove the "new" modules, close it back up, and boot up normally. You will be able to enter Safe Mode while it is in reboot loop error. You can indeed put different sizes of RAM modules in a motherboard. What matters is that they match in Type, which means fsb, CAS latency, etc. It is a good idea to buy all from the same vendor, but you know now what to watch out for, and no lasting harm occurs after removing offending modules and booting normally. So, you really have nothing to lose in trying to make it work, and at the very least it may work long enough for you to purchase additional modules from the manufacturer you bought the 2 GB module from. I always install the full 4 GB in a 32 bit system even though I know the system will not see it all because it gives me the most optional RAM. By optional I simply mean the best chance for the most the system can see. It all depends on the hardware on the system. In Vista, the Video card RAM is better utilized, so if you use Vista operating system be sure to upgrade to a card with at least 512 MB of onboard memory. That means you would possibly have that additional 512 free that the video card would otherwise, "take" from the modules. It is all about Addressing Space. Physical memory is mapped to the Addressing Space, and as the upper forth GB is reserved for system uses in a 32 bit OS, if your hardware needs a full GB, then the fourth GB of physical memory cannot be mapped. So, go for it, good luck and have a nice day.