Please help me figure out how I should upgrade my memory

[Citadel535]

Hi everyone,

I have a Pentium D running Vista Home Premium with 1024MB memory. I looked up via SiSoft Sandra that my memory is being identified as Siemens 64T64000HU3SA (I googled it and found some Dell info that says that part number is Infineon memory actually) memory and currently have 2x 512 mb PC-5300 memory modules. Now I was looking at Crucial to upgrade my memory and it says two things that I am unsure of, one is what cas latency should I go with with ram and can I mix and match paired memory modules.

For example, Sandra reports my Standard Timings as 5.0-5-5-15 (tCL-tRCD-tRP-tRAS) so I believe that means I have cas latency 5 ram. Am I wrong about this? I want to buy an upgrade but theres no point in getting faster memory when this memory is already running at a slow cas latency I think. Also since I have 2x 512MB modules, can I put 2x1024 in there (so I would have 2x1024 and 2x512 for 3gb total) with the modules or would I have to get 2x512MB modules to go with the 2x512 I already have (for a 2GB total)?

Please help me out! Thanks!

 

[JustaGeek]

Please read the thread and let me know if that answers your questions:

http://forums.anandtech.com/me...=2071307&enterthread=y

I would recommend the same memory speed/timings/voltage. You should be fine with 2x1GB modules, for a total of 3GB RAM, but read the article below to understand the issues involved.

http://www.dansdata.com/askdan00015.htm

 

[Citadel535]

I think I "should" be ok with getting 2x1gb then and putting that in. My only other question is am I reading sandra correctly with the timings that indicate that my memory is cas latency 5? It's reported as 5.0-5-5-15 (tCL-tRCD-tRP-tRAS).

 

[JustaGeek]

SANDRA will only read the SPD (Serial Presence Detect) chip in the memory modules.

The label attached to the memory modules (if present) will give you the manufacurer's rated latencies/voltage for the memory.

The manufacturers often "relax" the timings to e.g. 5-5-5-15 and 1.8V to allow the system boot the first time, and permit the user to enter the rated latencies and voltage, like 4-4-4-12 2.1V manually in BIOS.

If there is no label, check the manufacturer's website, or contact their support.